2,10-disubstituted-1,2,3,4-tetrahydrobenzo(bhq (1,6)naphthyridines useful as cns depressants

ABSTRACT

This invention concerns 1,2,3,4tetrahydrobenzo(b)(1,6)naphthyridines, 1,2,3,4,4a,5,10,10aoctahydrobenzo(b)(1,6)naphthyridines and the pharmacologically acceptable acid addition salts thereof which are pharmacologically active as central nervous system depressants which are useful in producing a calming effect in warm-blooded animals. Further, this invention concerns a process for the preparation of 10-amino-1,2,3,4tetrahydrobenzo(b)(1,6)naphthyridines.

O United States Patent [151 3,674,790

Wolf et al. July 4, 1972 [54] 2,l0-DISUBSTlTUTED-1,2,3,4- [56] References Cited TETRAHYDROBENZO[BHQ UNITED STATES PATENTS [1,6]NAPHTHYRIDINES USEFUL AS 3 401 201 9,1968 w l 260mg x a ton CNS DEPRESSANTS 3,503,981 3/1970 Suess et al. ..260/288 [72] inventors: Milton Wolf, West Chester; James L.

Diebold, l-lavertown, both of Pa. OTHER PUBLICATIONS Kempter et al., Chem. Ber., Vol. 98, pp. 419- 427 (1965) [73] Asslgneel 2522; g v Products Corporation Chem. Abstn, Vol. 70, C01. 967804, abstracting France 1,514,010. [22] Filed: May 1, 1970 p Primary Examiner-Donald G. Daus [211 App] 33932 Attorney-Andrew Kafko, Joseph Martin Weigman, Dwight J 7 Related Application Data Potter, Vito Victor Bellino and Robert Wiser [60] Division of Ser. No. 760,063, Sept. 16, 1968, Pat. No. [57] ABSTRACT 3 580 915 which is a continuation-in-part of Ser. Nos.

ThlS invention concerns l,2,3,4-tetrahydrobenzo[b][ if: :2 i322 g g? g g 1,6]naphthyridines, l,2,3,4,4a,5,l0,l0a-octahydrobenzo[b][ S z l966 a z an 1,6]naphthyridines and the pharmacologically acceptable cp a an one acid addition salts thereof which are pharmacologically active as central nervous system depressants which are useful in [52] US. Cl. ..260/286 R, 260/283 BI, 260/283 S, producing a calming effect in warmblooded animals Further 260/288 260/288 260,287 R this invention concerns a process for the preparation of i0- [5 l 1 Int. Cl. ..C07d 39/00 amino lz,3'4 tctrahydrobenzo[bl[ l6lnaphthyfidines [58] Field of Search ....260/288 R, 283 S, 288 A, 287 R 43 Claims, No Drawings 2 1 O-DISUBSTITUTED- 1 ,2,3 ,4-TETRAHYDROBENZO[B]f I l ,6]NAPHTHYRIDINES USEFUL AS CNS DEPRESSANTS This application is a division of US. application Ser. No. 760,063 now US. Pat. No. 3,580,915 of May 25, 1971, entitled l ,2,3,4-Tetrahydrobenzo[b][ 1,6]Naphthyridine Derivatives, filed on Sept. 16, 1968 by Milton Wolf and James L. Diebold, which in turn is a continuation-in-part of now abandoned US. patent applications: Ser. No. 533,802, entitled 10-Aminobenzo[b][1,6]Naphthyridines," filed on Mar. 14, 1966 by Milton Wolf; Ser. No. 533,793, entitled l,2,3,4- Tetrahydrobenzo[b][ 1 ,6]Naphthyridine Derivatives," filed on Mar. 14, 1966 by Milton Wolf and James L. Diebold; and Ser. No. 581,756, entitled l,2,3,4-Tetrahydrobenzo[b][ 1,6 ]Naphthyridine Derivatives," filed Sept. 22, 1966 by Milton Wolf and James L. Diebold.

This invention is directed to novel compounds classified in the art of organic chemistry as benzonaphthyridines and to a process for making some of these compounds. More particularly, the present invention is concerned with 1,2,3,4- tetrahydrobenzo[b][ l ,6]naphthyridines and 1,2,3,4,4a,5,10,l[b][1,6]naphthyridine derivatives which in standard and accepted pharmacological tests have demonstrated central nervous system depressant activity which is useful in producing a calming effect in warmblooded animals.

In its composition aspect, the claimed invention resides in a composition of matter having a tetrahydro or a octahydrobenzo[b]d[ 1,6]naphthyridine substituted These compounds are exemplified by the following formulas:

wherein R and R are selected from the group consisting of hydrogen, halogen, nitro, lower alkyl, lower alkoxy, lower alkylthio, lower alkylsulfonyl, carbamoyl, sulfamoyl, and trifluoromethyl; R is selected from the group consisting of hydrozino, amino, aminoanilino, anilino, di(lower)al kylamino(lower)alkylamino, amino(lower)a.lkylthio, phenyl, sulfamylphenyl, carboxyphenyl, phenylhydrazino, halophenyl, lower alkylphenyl, lower alkoxyphenyl, lower alkylthiophenyl, phenoxy, phenthio, morpholino, pyridyl, thienyl, and furyl, 4- alkyl- 1 -piperziny1; and R is selected from the group consisting of hydrogen, amidino, lower alkyl, di(lower)alkyl, phenyl, lower alkylphenyl, halophenyl, phen(lower)alkyl, benzoyl, lower alkanoyl, halo(lower) alkanoyl, dihalo(lower)alkanoyl, lower alkanoyloxy, di( lower) alkylamino(lower)alkanoyl, lower alkylsulfonyl, phenylsulfonyl, lower alkylcarbamoyl, lower alkoxy(lower)alkyl, di(lower) alkylamino(lower)alkyl, dihydroxy(lower)alkyl and 5,5-dimethyl-3-oxo-l-cyclohexenl-yl; R. and R when taken separately are both selected from the group consisting of hydrogen, dimethyl, lower alkyl, phenyl, halophenyl, lower alkylphenyl, lower alkoxyphenyl and phen(lower)alkyl, and when R and R are concatenated they form an ethano bridge; and the pharmacologically acceptable acid addition salts thereof. As employed herein the terms lower alkyl", lower alkoxy", lower alkanoyl" and the like are meant to include both branched and straight chain hydrocarbon moieties having from about one to about six carbon atoms.

The compounds of the present invention possess the inherent physical properties of being relatively high melting yellowish to colorless solids, and substantially insoluble in water. Examination of these compounds produced by the hereinafter described processes reveals data confinning the molecular structures hereinbefore set forth. The aforementioned physical characteristics, taken together with the nature of the starting materials and the mode of synthesis positively confirm the structure of the compounds of this invention.

nucleus.

The new and novel compounds of the above formula (1) properly are called tetrahydrobenzonaphthyridines. Typical examples thereof are: 8chloro-l,2,3,4-tetrahydro2-methyl- 10-phenylbenzo[b][ 1,6]naphthyridine and 2-benzyl-8-chloro- 1 ,2,3,4-tetra.hydro- 1 0-phenylbenzo[b][ 1,6 ]naphthyridine. The compounds of the present invention of formula (1) wherein R is amino, aminoanilino, anilino, hydrazino and phenyl hydrazino may exist in two forms, as shown in by following tautomeric structures:

wherein R, R R R, and R are defined as above; and R is selected from the group consisting of hydrogen, aminophenyl, phenyl, amino and phenylamino. For the purpose of simplicity these tautomers (a) and (b) shall hereinafter be designated and named as the IO-position amino compounds of formula (a), for example: IO-amino-l,2,3,4-tetrahydro-2-methylbenzo[b][ 1,6]naphthyridine; 10-(o-aminoanilino)-7-chlorol ,2,3,4-tetrahydro-2-methylbenzo[b] l ,6]naphthyridine; l 0- anilino-8-chlorol ,2,3,4-tetrahydro-2-methylbenzo[ b][ l ,6] naphthyridine; (8-chlorol ,2,3 ,4-tetrahydro-2-methylbenzo [b][ l,6]naphthyridin l Oyl )hydrazine; and l-( 7-chlorol,2,3,4-tetrahydro-2-methylbenzo[ b][ 1,6]naphthyridinl 0- yl) -2-phenylhydrazine. It should be understood, however, that the present invention also encompasses and includes the corresponding IO-position imino compounds of formula (b). When the compounds of this invention are represented by the formula (11) they are designated octahydrobenzonaphthy ridines," such as: 2benzyl-8-chloro-l,2,3,4,4a,5,l0,10a-octahydrobenzonaphthyridine and 8-chloro-l ,2,3,4,4a,5 l 0, l 0 a-octahydroZ-methyl-l0-phenylbenzo[b][ l ,6]naphthyridine.

Some of the tetrahydrobenzonaphthyridines of the present invention may be prepared by the interaction of a o-aminocarbonyl compound with a 4-piperidone. This first process is further elucidated in the following reaction scheme:

I N-Ra Condensation NH: owau I R1 R wherein R, R,, R R and R are defined as above, and R is selected from the group consisting of phenyl, sulfamylphenyl, carboxyphenyl, halophenyl, lower alkylphenyl, lower alkoxyphenyl, lower alkylthiophenyl, pyridyl, thienyl, and fury]. This reaction is conducted in the presence of a strong acid at a temperature from about 70 to about 210 C. for a period of about fifteen minutes to about four hours. Preferably, this reaction is conducted in polyphosphoric or trifiuoroacetic acid. When the reaction is complete, the reaction mixture is cooled and then admixed with an ice-water mixture. The resulting solution is then filtered and made basic to separate the appropriate tetrahydrobenzonaphthyridine.

Alternatively, the above-defined tetrahydrobenzonaphthyridines may be prepared by heating the reactants to fusion with the passage of hydrogen chloride gas through the melt. This operation results in an exothermic reaction accompanied by the evolution of water. To complete the reaction the reaction mixture is again heated up to about 200-2l0 C. The reaction mixture is then cooled, triturated with an alkanol and the product recovered as the hydrochloride salt by conventional means.

In accord with the new and novel process of the present invention, the 10-arninotetrahydrobenzonaphthyridines of this invention may be prepared by the reaction of a 2- aminobenzonitrile with an appropriate 4-piperidone. This second process is exemplified by the following reaction scheme:

wherein R, R,, R R and R are defined as above. The reaction is effected by heating a substantially equimolar mixture of the reactants, in the presence of a strong acid, at a temperature from about 140 to about 200 C. for a period of from about one-half hour to two hours. Preferably, this reaction is conducted in polyphosphoric acid at about 150 C, for about one hour. By strong acid as employed in these first two processes is meant any organic or inorganic acid which dissolves the reactants and does not interfere with their interaction. Although many such acids may be employed, as will suggest themselves to those skilled in the art, excellent results have been obtained with polyphosphoric, trifluoroacetic, acetic and alkanesulfonic and arylsulfonic acids, for example, benzenesulfonic, and toluene-sulfonic acid, methylsulfonic acid and ethylsulfonic acid. I

After the reaction is complete, the reaction mixture is cooled and basified with an aqueous alkaline solution, for example, sodium hydroxide, potassium hydroxide, sodium bicarbonate and sodium carbonate. Thereafter, the aminotetrahydrobenzonaphthyridine is obtained by conventional methods such as filtration and crystallization from a suitable solvent.

The other tetrahydrobenzonaphthyridines of this invention may be prepared by a third process which is depicted by the following reaction scheme:

wherein R, R R R and R are defined as above, and R is is selected from the group consisting of aminoanilino, anilino, di(lower)alkylamino(lower)alkylamino, phenoxy, morpholino, 4-alkyl-l-piperazinyl, phenthio, amino(lower)alkylthio, hydrazino and phenylhydrazino. The 10- chlorotetrahydronaphthridine intermediates are prepared by the interaction of an anthranilic acid, an appropriate 4- piperidone and phosphorus oxychloride at about the reflux temperature of the reaction mixture for a period of about 1 to about 4 hours. The reaction mixture is then evaporated, the residue dissolved in a water-immiscible organic solvent, e.g. methylene chloride which is then added to a cold aqueous alkaline solution, e.g. ammonium hydroxide. Thereafter, the 10- chlorotetrahydrobenzonaphthyridine intermediate is separated by standard procedures, e.g. the water layer is washed, dried and evaporated to afford the intermediate which may be further purified by crystallization from a suitable solvent, e. g. a liquid alkane.

The tetrahydrobenzonaphthyridine of this invention wherein R is aminoanilino, anilino, di(lower)alkylamino(lower) alkylamino, phenoxy, morpholino and 4- alkyl-l-piperazinyl are prepared by the condensation of an above-prepared lO-chlorotetrahydrobenzonaphthyridine intermediate with an appropriate proton donor reactant, e.g. aminoaniline, aniline, a di(lower) alkylamino(lower)alkylamine; phenol and morpholine. The reaction is effected by admixing a lO-chlorotetrahydrobenzonaphthyridine with phenol and heating the resulting mixture, under an inert atmosphere e.g. nitrogen, to about C. for a period of about 15 to about 30 minutes. Thereafter, the proton donor reactant is slowly added and the reaction mixture is then heated to about reflux temperatures for a period of about 5 to about 8 hours. When the reaction is complete, the resulting product is recovered by standard procedures, e.g. the product is dissolved in a water-immiscible organic solvent e.g. methylene chloride, extracted with an aqueous alkali metal hydroxide solution, dried, evaporated to dryness and the residue is then recrystallized from a suitable solvent e. g. benzene.

The tetrahydrobenzonaphthyridines of this invention wherein R is arylthio and alkylthio, e.g. phenthio and amino (lower)alkylthio areprepared by the condensation of an above-prepared 10-chlorotetrahydrobenzonaphthyridine with an appropriate mercaptan reactant, e.g. phenyl mercaptan and an amino(lower)alkyl mercaptan. The reaction is elTected by admixing a lO-chlorotetrahydrobenzonaphthyridine, an appropirate mercaptan, and from about 1 to about 2 molar excess of an aqueous alkali metal hydroxide solution in an alkanol and then heating the resulting mixture to about reflux temperatures for a period of about 1 to about 3 hours. When the reaction is complete, the product, a IO-thiotetrahydrobenzonaphthyridine, is separated by conventional recovery methods. For example, the reaction mixture is evaporated to dryness, the residue dissolved in a water-immiscible organic solvent, e.g. methylene chloride, this organic layer is then evaporated to dryness and the residue is recrystallized from an appropriate solvent e.g. hexane. The 10- arylthiotetrahydronaphthyridines may also be prepared by the condensation reaction described in hereinafter Example LVlIl.

The tetrahydrobenzonaphthyridines of this invention wherein R,, is hydrazino and phenylhydrazino are prepared by the condensation of an above prepared 10- chlorotetrahydrobenzonaphthyridine with an appropriate hydrazine this reaction is conducted in an alkanol at about reflux temperatures for a period of about 1 to about 8 hours. Thereafter, the resulting product, a tetrahydrobenzonaphthyridinyl hydrazine, is separated by standard procedures, as exemplified in hereinafter Examples LX-LXI.

The above-described 2-lower alkanoyloxy tetrahydrobenzonaphthyridines, the 2-halo(lower)alkanoyl tetrahydrobenzonaphthyridines, the 2-amidino tetrahydrobenzonaphthyridines, the 2-dihydroxy(lower)alkyl tetrahydrobenzonaphthyridines, the 2-di(lower)alkalmino(lower)alkanoyl tetrahydrobenzonaphthyridines, and the 2-dihalo(lower)alkanoyl tetrahydrobenzonaphthyridines may also be prepared by the procedures described in detail in the hereinafter listed Examples XIX to XXV.

The octahydrobenzonaphthyridine compounds of the present invention are prepared by the hydrogenation of their corresponding above prepared tetrahydrobenzonaphthyridine, as exemplified by the following reaction:

ltz Rt lit:

l ll

wherein R, R R R R, and R, are defined as above. Although various reduction procedures may be employed, a preferred method to effect this conversion is the use of a reducing agent such as hydrogen gas. Utilizing this preferred method, a tetrahydrobenzonaphthyridine is admixed with glacial acetic acid and platinum oxide at about 30 C., under a hydrogen pressure of about 50 psi, for a period of about 24 hours. Thereafter, the product is separated by evaporation of the excess acetic acid and the residue is dissolved in water, basified and recrystallized to yield the appropriate octahydrobenzonaphthyridine.

As is evident from the above-described methods of producing the tetrahydrobenzonaphthyridine and octahydrobenzonaphthyridine compounds of this invention, these compounds can be recovered either in the form of their acid addition salts or as the free bases. These tetrahydrobenzonaphthyridine and octahydrobenzonaphthyridine bases can be converted to their acid addition salts by reacting them with the usual acids, e.g. hydrochloric, hydrobromic, hydroiodic, sulfuric and phosphoric or with an organic acid, for example, citric, acetic, benzoic, methanesulfonic or p-toluenesulfonic. While the free bases have the same pharmacological properties as their acid addition salts, they are more often utilized in the preparation of such salts rather than directly for their pharmacological effects.

In accord with the present invention, the new and novel tetrahydrobenzonaphthyridine and octahydrobenzonaphthyridine compounds of this invention have been found to possess interesting pharmacological properties. More particularly, these compounds, in standard pharmacological tests, have exhibited utility as central nervous system depressants which are useful in producing a calming effect, particularly in laboratory and domestic animals.

In the pharmacological evaluation of the central nervous system depressant compounds of this invention the in vivo effects of the compounds of this invention are tested as follows:

The compound is administered orally as a 1 percent suspension emulsified with polyethylene oxide sorbitan monooleate to three mice 14 to 24 grams) at each of the following doses: 400, 127, 40, 12.7 and 4.0 mg./kg. The animals are watched for a minimum of two hours during which time signs of general stimulation (i.e., increased spontaneous motor activity, hyperactivity on tactile stimulation, twitching), general depression (i.e., decreased spontaneous motor activity, decreased respiration) and autonomic activity (i.e., miosis, mydriasis, diarrhea) are noted. The animals are tested for changes in reflexes (i.e., flexor, extensor) and are rated for their Sedative-Ataxic Score by use of a pole climb and inclined screen for the presence of sedationataxia [Kouzmanoff et al, J. Pharrn. Exp. Ther. I44, 40A (1958)]. The Eddy Hot'Plat Method [Nathan B. Eddy and Dorothy Leimbach, Jr. Pharmacol. Exper. Therap., 107, 385 (1953)] is used to test for analgesia. The experiment is terminated by subjecting each animal to a maximal electroshock to test for anticonvulsant activity.

The tetrahydrobenzonaphthyridine and 0ctahydrobenzonaphthyridine compound of this invention in the above test procedure produce decreased motor activity when administered at a dosage range from 12.7 to 400 mg./kg.; produce decreased respiration when administered at a dosage range from 40 to 400 mg./kg. and rate a sedative-ataxic score of l2 when administered at a dosage range from 40 to 400 mg./kg. There were no deaths at the highest dose used, 400

When the tetrahydrobenzonaphthyridine and octahydrobenzonaphthyridine compounds of this invention are employed as central nervous system depressants to produce a calming effect in warm-blooded animals, e.g., mice, rats, rabbits, dogs, cats, monkeys, etc. they may be administered alone or in combination with pharrnacologically acceptable carriers, the proportion of which is determined by the solubility and chemical nature of the compounds, chosen route of administration and standard biological practice. For example, they may be administered orally in the form containing such excipients as starch, milk sugar and so forth. They may also be administered orally in the form of solutions or they may be injected parenterally. For parenteral administration they may be used in the form of a sterile solution containing other solutes, for example, enough saline or glucose to make the solution isotonic.

The dosage of the present tetrahydrobenzonaphthyridines and octahydrobenzonaphthyridines compounds when employed as central nervous system depressant agents will vary with the form of administration and the particular compound chosen. Furthermore, it will vary with the particular subject under treatment. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the compound. Thereafter, the dosage is increased by small more ments until the optimum effect under the circumstances is reached. In general, the compounds of this invention are most desirably administered at a concentration level that will generally afi'ord efi'ective results without causing any harmful or deleterious side effects.

Further, it has been suprisingly found that 8-chloro-1,2,3,4- tetrahydro-l l ,3,3-tetramethyll Ophenylbenzo [b] l ,6]naphthyridine and 8-chloro-1,2,3,4-tetrahydro-IO-phenylbenzo[b][1,6]naphthyridine of the present invention also possess valuable amebicidal activity. In particular, when tested in standard in vitro screening procedures these two compounds have demonstrated anti-amebic activity, especially against Endameba histolytica and are, therefore,'useful as anti-amebic agents.

In the amebicidal evaluation of these two compounds of this invention, the test compound is incorporated and diluted in the aqueous phase of Boeck-Drbohlav diphasic medium fortified with rice starch. The medium is inoculated with polybacteria and a known number of trophozoites of E. histolytica NIH 200. After 48 hours incubation at 35 C., the trophozoites are counted. The procedure is derived from Thompson, et al., Antibo. and Chemo, 6, 337-50 (1956). The endpoint is expressed as the percent of E. histolytica killed at a particular concentration (pg/ml.) of test compound. In this test, 8- chloro-l ,2,3,4-tetrahydrol ,l ,3 ,3-tetramethyll O-phenylbenzo [b][ 1,6]naphthyridine averaged about a percent kill of E. histolytica at a concentration of pg/ml. and 8-chloro- 1 ,2,3,4-tetrahydro-10-phenylbenzo[b][ 1,6]naphthyridine averaged about a percent kill of E. histolytica at a concentration of about 5 ug./ml.

The anti-amebic activity of these two compounds of this invention can be utilized for washing equipment in hospitals and homes, instruments used in medicine and bacteriology, clothing used in bacteriological laboratories, and floors, walls and ceiling in rooms in which a background free of E. histolytica is desired.

Still further, it has been unexpectedly found that 8-chloro- 1 ,2,3 ,4-tetrahydro- 1 I ,3,3-tetrahydromethyl- 1 O-phenylbenzo[b][ 1,6]naphthyridine; 8-chlorol ,2,3,4-tetrahydro-2- phenethyl-10-phenylbenzo[b][ l ,6 ]naphthyridine; 8-chloro- 1 ,2,3 ,4-tetrahydro-2-methyl-10-phenyl-1 ,3-ethanobenzo[ b][ 1 ,6]naphthyridine; l,2,3,4-tetra.hydrol ,1 ,3 ,3-tetramethyl- 10-(p-tolyl) benzo[b][ 1,6]naphthyridine; 6-chloro- 1 ,2,3,4- tetrahydro-l,1,3 ,3-tetramethyll0-phenylbenzo[b][ 1,6] naphthyridine; 7-chl0rol ,2,3 ,4-tetrahydro-l ,1 ,3 ,3- tetramethyll 0-( p-methyl-thiophenyl )benzo[ b] 1 ,6] naphthyridine; 7,8-dimethoxy-l ,2,3 ,4-tetrahydro-l ,1 ,3,3- tetramethyll 0-( p-methoxyphenyl)benzo[b][ l ,6 ]naphthyridine; 8-chloro-2-chloroacetyl-1,2,3 ,4- tetrahydrol0-phenylbenzo[b][ 1,6]naphthyridine; 2-amidino- 8-chloro-l ,2,3 ,4-tetrahydro- 1 0-phenylbenzo[b][ l ,6] naphthyridine; m-( 2-benzyl-8-chloro-l ,2, 3 ,4-tetrahydrol0- benzo[b][ 1,6]naphthyridinyl)benzenesulfonamide; 2-benzyl- 6-chloro- I ,2,3,4-tetrahydrol 0-phenylbenzo[b][ 1 ,6] naphthyridine; 2-benzyl-7-chlorol ,2,3 ,4-tetrahydro- 1 O-phenylbenzo[b][ 1,6]naphthyridine; l0-anilino-7-chloro-l ,2,3,4- tetrahydro-2-methylbenzo[b 1 ,6]naphthyridine; 7-chlorol ,2,3,4-tetrahydro-2-methyl-10-(phenylthio)benzo[b][ 1,6] naphthyridine; 1 7-chloro- 1 ,2,3 ,4,-tetrahydro-2-methylbenzo[b][ l ,6]naphthyridin- 1 -yl )-2-phenylhydrazine; l0- anilino-8-chloro-1,2,3,4-tetrahydro-2-methylbenzo[b][ 1,6] naphthyridine; and 3-(8-chloro-1,2,3,4-tetrahydro-IO-phenylbenzo[b][ 1,6]naphthyridin-2-yl)-5,5-dimethyl-2cyclohexenl-one also possess valuable antibacterial properties. More particularly, these seventeen compounds, when tested in standard bacteriological procedures have exhibited utility as antibacterial compounds, especially as antitubercular agents.

The in vitro bacteriocidal activity of these seventeen compounds of this invention against tubercle bacilli is tested by the following procedure:

A stock solution containing 1,000 ug/ml of a test compound in a suitable vehicle e.g., water is prepared. One ml. quantities of various dilutions of this stock solution are added to individual tubes containing 9 ml. of medium to give final concentrations within the range of 0.01 to 100 ig/m1. These tubes are then seeded with 0.1 ml. of standardized bacterial suspension and incubated for 2 weeks at 37 C. The media employed in Dubos Oleic acid liquid medium and the stock cultures are maintained on Dorset Egg Agar. The organisms used are M. tuberculosis, human type, strain H 37 Rv and M. tuberculosis, bovine type, strain Ravenel. The results are expressed as minimal inhibitory concentration (MIC) in ug/ml which is the least concentration of a compound that will completely prevent the growth of the organism. 1n the above test, these seventeen tetrahydrobenzonaphthyridine compounds of this invention completely inhibit the growth of tubercle bacilli at a MIC in the range of about 0.5 to about 50 ug/ml.

As has been mentioned hereinabove, these latter seventeen tetrahydrobenzonaphthyridine compounds of this invention are also biocidally active, as antibacterial agents. ln this connection, they exhibit activity against pathogenic bacteria, specifically in vitro antitubercular activity as bacteriocidal agents against tubercle bacteria. Their bacteriocidal properties make these seventeen compounds valuable in biocidal compositions in a variety of important fields for use. For example, they can be formulated and used in bacteriocidally active institutional cleaning compositions, and in soaps and detergents. These compositions are employed for washing equipment in hospitals and homes, instruments used in medicine and bacteriology, clothing used in bacteriological laboratories, and floors, walls and ceiling in rooms in which a background free of tubercle bacteria is desired. When either the two above-described anti-amebic agents or the seventeen aforesaid anti-tubercular agents are used for their biocidal purposes, they are applied according to their desired end-uses as powders, solutions, suspensions and the like, containing the active substance generally in concentrations of 0.1 to 0.7 percent by weight, or even as much as 1, 1.5 percent, 1.8, 2 percent and up to about percent. in washing solutions, e.g., for hospitals and homes, the active anti-amebic and anti-tubercular compounds of this invention will be used generally in the range of from about 0.02 to 0.25 percent by weight.

Although, in common with most organic substances, with relatively high molecular weights, the anti-amebic and anti-tubercular compounds of this invention have limited solubility in water, those skilled in the art will have no great difficulty in formulating them into a wide variety of biocidally-active compositions. in general, standard techniques can be employed and, where necessary, advantage is taken of the ability of these compounds to form salts with acids, which have enhanced solubility in water. The active compounds per se can be made up in dilute aqueous solution. They can also be formulated as suspensions or solutions in an aqueous vehicle containing an organic co-solvent, such as, for example, an alkanol. Also, aqueous vehicles containing emulsifying agents, such as sodium lauryl sulfate, and relatively high concentrations, e.g., up to about 5 percent by weight, of the compounds of this invention can be formulated by conventional techniques.

The reactants employed in the first three above-described processes are known compounds which are commercially available and/or prepared by well known procedures. In this regard, the 4-piperidone" reactants may be prepared by the methods described in S. M. McElvain and K. Rorig in J. Am. Chem. Soc. 70 1829 (1948); S. M. McElvain in J. Am. Chem. Soc. 46, 1725 (1924); S. M. McElvain in J. Am. Chem. Soc. 48, 2179 (1926); S. M. McElvain and G. Stork in J. Am. Chem. Soc. 68, 1049 (1946); J. R. Thayer and S. M. McElvain in J. Am. Chem. Soc. 49, 2862 (1927); J. B. Baty, G. Jones and C. Moore in J. C. pg. 2645 (1967); and J. Guareschi, Ber. 28, 160(1895).

The o-aminocarbonyl compound reactants employed in the first above-described process may be prepared by the procedures described by: G. N. Walker in J. Org. Chem., 27 1929 (1962); F. Korte and O. Behner in Ann. 621, 51 (1959); S. Bell et al., in US. Pat. No. 3,516,992 ofJune 23, 1970 entitled 3-(2-Amino-5-Halo, S-Alkyl-and-S-Alkoxy)Benzene Sulfonamides;" L. H. Stemback et al. in J. Org. Chem. 26, 448 (1961); and L. H. Stembach et al. in J. Org. Chem. 27, 3781 (1962).

The 2-aminobenzonitrile" reactants employed in the new and novel second above-described process may be prepared by the procedures described by: S. Gabriel in Ber. 36, 804 (1903); J. Pinnow and C. Samman in Ber. 29, 624 (1896); W. Borsche, H. Weussman and A. Fritzsche in Ber. 57, 1151 (1924); and L. H. Stembach et al. in J. Org. Chem 27, 3781 1962).

The anthranilic acid" reactants employed in the third above-described process may be prepared by the procedures described in the text -Chemistry of Carbon Compounds Vol. 3A pg. 576-8, Editor E. H. Rodd, Elsevien, New York (1954).

EXAMPLE I Hydrogen chloride (gas) is bubbled into a hot melt of 2- amino-5-chlorobenzophenone (11.58 g., 0.050 m.) and 1- methyl-4-piperidone (5.66 g., 0.050 m.) for several minutes. An exothermic reaction takes place, with the concurrent evolution of water, and the melt solidifies. The melt is heated at ZOO-210 C. for one-half hour, cooled and triturated with 2- propanol to yielding a colorless solid which is recrystallized from methanol-water. In this manner, colorless prisms of 8- chlorol ,2,3,4-tetrahydro-2-methyll 0-pheny1ben2o[b][ 1,6] naphthyridine hydrochloride are obtained, (1.4 g., 9%), mp 285-90bL C.

Anal. Calcd. for C H cl N C, 66.08; H, 5.26; N, 8.12.

Found: C, 65,76; H, 5.10; N, 8.12.

EXAMPLE [1 A mixture of 2-amino-S-chlorobenzophenone (1 1.58 g., 0.050 m.), polyphosphoric acid (330 g.), and 1-methyl-4- piperidone (5.66 g., 0.050 m.) is heated gradually to 205 C. with stirring, and maintained at that temperature for one-half hour. The partially cooled reaction mixture (-l 10 C.) is poured with stirring into a mixture of ice and water (500 g.). The resulting solution is filtered to remove a small amount of insoluble solid, then basified with 50 percent sodium hydroxide cc.). The product separates as a crystalline solid, which is collected, washed thoroughly with water, and dried, m.p. 148 C. (uncorr.). Recrystallization from hexane yields pale yellow prisms of 8-ch1oro-1,2,3,4-tetrahydro-2-methyl- 10-phenylbenzo[b][1,6]-naphthyridine, (9.0 g., 58.4 percent) m.p. 149.0l49.5 C. (uncorr.).

Anal. Calcd. for C H CIN C, 73.90; H, 5.55; N, 9.07.

Found: C, 73,61; H, 5.28; N, 9.22.

Repeating of the above reaction at C. for one hour produces a quantitative yield of the same product, m.p. 149.0149.5 C. (uncorr).

EXAMPLE III A mixture of 2-amino-5-chlorobenzophenone (1 1.0 g.) polyphosphoric acid (330 g.), and l-benzyl-4-piperidone (5.8 g.) is heated gradually to about 200 C. with stirring, and maintained at that temperature for three quarters of an hour.

The partially cooled reaction mixture 100 C.) is poured with stirring into a mixture of ice and water (500 g.). The resulting solution is filtered and then basified with 50 percent sodium hydroxide (120 cc.). The product separates as a yellow solid, which is collected, washed thoroughly with water and dried, m.p. 164-l65.5 C. (uncorr.). Recrystallization from 2- propanol affords pale yellow, rhomboid crystals of 2-benzyl-8- chloro1 ,2,3 ,4-tetrahydro- 1 -phenylbenzo[ b] 1,6] naphthyridine (19.35 g., 50.3 percent), m.p. 166.0166.5 C. (uncorr.). v

Anal. Calcd. for C H ClN C, 78.00; H, 5.50; N, 7.28.

Found: C, 77.76; H, 5.27; N, 7.38.

In a similar manner, 2-benzyl-7-bromo-l,2,3,4-tetrahydro- 10-( p-to1yl)bcnzo[b][ 1,6]naphthyridine and 2-acetyl- 1 ,2,3,4- tetrahydro-10-(p-methoxyphenyl)-8-methylbenzo[b][ l ,6] naphthyridine are obtained.

EXAMPLE lV Dry hydrogen chloride is passed into another solution of the above prepared 2-benzyl-8-chloro- 1 ,2,3 ,4-tetrahydrol 0- phenylbenzo[b][1,6]naphthyridine. Thereafter, the corresponding hydrochloride salt is recrystallized from absolute ethanol to yield colorless crystals of 2-benzy1-8-chloro-l,2,3,4 -tetrahydrol 0-phenylbenzo[b][ 1,6 ]naphthyridine hydrochloride, m.p. 271.5275 C. (uncorr.).

Anal. Calcd. for C H Cl N C, 71.25; H, 5.27; N, 6.65.

Found: C, 71.46; H, 5.42; N, 6.73.

EXAMPLE V 2-Amino-5-chlorobenzophenone (23.17 g., 0.10 m.), polyphosphoric acid (600 g.), and l-(2-phenethyl)-4- piperidone (20.33 g., 0.10 m) are admixed, heated to 150 C. with stirring, and maintained at that temperature for 1 hour. The reaction mixture is cooled and, thereafter, is poured with stirring into a mixture of ice and water (1,000 g. The resulting solution is filtered to remove a small amount of insoluble solid, then basified with 50 percent sodium hydroxide (240 cc.). The resulting 8-chloro-1,2,3,4-tetrahydro-2-(2- phenethyl)-10-phenylbenzo[b][ 1 ,6]naphthyridine separates as a solid, which is dissolved in ether and treated with dry hydrogen chloride. In this manner, is obtained 8-chlorol ,2,3 ,4-tetrahydro-2-( 2-phenethyl 1 0-phenylbenzo[ b] 1,6]- naphthyridine hydrochloride, m.p. 268269.5 C.

Anal. Calcd. for C H Cl N C, 71.71; H, 5.56; N, 6.44.

Found: C, 71.49; H, 5.49; N, 6.56.

Similarly, the following tetrahydrobenzonaphthyridine hydrochlorides are synthesized:

l0( p-bromophenyl )-2-ethyll ,2,3,4-tetrahydro-7- nitrobenzo[b][ 1,6]naphthyridine hydrochloride;

l0-phenyll ,2,3 ,4-tetrahydro-Z-methylsulfonylbenzo l ,6]naphthyridine hydrochloride;

8-ethyll ,2,3,4-tetrahydrol 0-phenyl-2-propionylbenzo[b 1,6]naphthyridine hydrochloride; and

7-ethoxy-2-ethyl-1 ,2,3 ,4-tetrahydrol O-phenyl-benzo[ b l ,61naphthyridine hydrochloride.

EXAMPLE VI ZAmino--chlorophenyl-2-pyridyl ketone (11.64 g., 0.05 m.) and l-methyl-4-piperidone (5.66 g., 0.050 rn.) are admixed, heated gradually with stirring to 145-150 C., and maintained at this temperaturefor 1 hour. The cooled reaction mixture is poured with stirring into a mixture of ice-water, filtered and then basified with a 45 percent potassium hydroxide solution. The resulting crystalline solid is collected by filtration, washed with water and dried. In this manner, is obtained 8-chloro-l ,2,3,4-tetrahydro-2-methyl-10-(2- pyridy1)benzo[b][ 1,6]naphthyridine.

Similarly, reacting 2-amino-5-iodophenyl-2-thienyl ketone and l-butyl-4-piperidone produces v 2-butyl-1,2,3,4- tetrahydro-8-iodol0-( 2-thienyl)benzo[b][ 1,6] naphthyridine, while reacting Z-aminophenyI-Z-furyl ketone with 4-piperidone yields -(2-fury1)-1,2,3,4- lclrzlhytlrohcnmlhl| l .6] naphthyridine.

EXAMPLE v11 Repeating the procedure of Example VI to react the following o-aminocarbonyl compounds and 4-piperidones, the hereinafter listed tetrahydrobenzo naphthyridines are obtained:

Reactants 2-amino-5-chlorobenzophenone and l-(p-chlorophenylsulfonyl )4-piperidone EXAMPLE Vlll Methyl iodide (2.29 g., 0.0162 m.) is added to a solution of 8-ch1oro-1 ,2,3,4-tetrahydro-2-methyl- 1 O-phenylbenzo b] 1,6]naphthyridine (5.0 g., 0.0162 m.) in absolute ether. The mixture is stored at room temperature in the dark overnight. The crystalline product which separates is recrystallized from 2-propanol to obtain colorless crystals of 8-chloro-1,2,3,4- tetrahydro-2,2-dimethyl- 1 O-phenylbenzo [b] l ,6 ]naphthyridi nium iodide (1.8 g., 24.4 percent), m.p. 255256.5 C. (uncorr.).

Anal. Calcd. for C H CIN C, 53.28; H, 4.47; N, 6.42.

Found: C, 53.12; H, 4.76; N, 6.42.

Similarly, ethyl iodide is reacted with 2-ethyl-1 ,2,3,4- tetrahydro-7-methoxyl O-phenylbenzo [b] 1,6 lnaphthyridine to produce 2,2-diethyl-l,2,3,4-tetrahydro-7-methoxy-10- phenylbenzo [b][1,6] naphthyridinium iodide.

EXAMPLE IX A solution of 2-benzyl-8-chloro-1,2,3,4-tetrahydro-10phenylbenzo [b][ 1,6] naphthyridine (6.0 g., 0.0156 in.) in glacial acetic acid ml.) containing platinum oxide (0.3 g.) is hydrogenated at room temperature, and an initial hydrogen pressure of 46.5 psi for a period of 24 hours. The excess acetic acid is distilled in vacuo, the residue dissolved in water, and then basified whereupon the crude product (5.87 g.) m.p. -l70 C. (uncorr.) separates. Recrystallization from cyclohexanohexane affords colorless crystals of 2-benzyl-8- chloro-l,2,3,4,4a,5,10,10a-octahydro-10-phenylbenzo [b][ 1,6]naphthyridine, (2.19 g., 27.7%) m.p. 19l.5-193.5 C. (uncorr.).

Anal. Calcd. for C H- ClN z C, 77.21; H, 6.48; N, 7.20; C], 9.11.

Found: C, 77.51; H, 6.32; N, 7.39; CI, 8.7.

EXAMPLE X Employing the procedure of Example 1X upon the hereinafter listed above prepared tetrahydrobenzonaphthyridines, the following octahydrobenzonaphthyridines are produced:

2-amino-5-chlorophenyl-2- thienyl ketone and l- (dimethylcarbamoyl )-4- piperidone 2-amino-5-propylbenzo phenone and l-(diethylcarbamoyl)-4-piperidone.

Reactant S-chloro-l ,2,3 ,4-tetrahydro- 2-methyll O-phenylbenzolb] 1,6]naphthyridine 2-benzyl-7-bromo1 .2,3,4- tetrahydro 1 O-(p-tolyl) benzo[b]a[1,6]naphthyridine 8-chloro-1,2,3,4-tetrahydro- 2-( B-phenethyl l0-phenylbenzo[ b]a[ 1,6]naphthyridine 8-chlorol ,2,3,4-tetrahydro- 2-methyll 0-( B-pyridyl )benzo [b][ 1,6]naphthyridine 8-chloro 1 ,2 ,3 ,4-tetrahydro- 2-dimethylcarbamoyll 0- (B-thienyl)benzo[b][ 1,6] naphthyridine A mixture of 2-amino-2,S-dichlorobenzophenone (26.61 g., 0.10 m.), polyphosphoric acid (500 g.) and l-methyl-4- piperidone (l 1.32 g., 0.10 m.) is heated heated to reflux with stirring, and maintained at that temperature for two hours. The cooled reaction mixture is poured with stirring into a mixture of ice and water (1,000 g.). The resulting solution is filtered and then basified with 50 percent sodium hydroxide (120 cc.). The product separates as a yellow crystalline solid, which is collected, washed thoroughly with water, and dried. In this manner, is obtained 8-ch1oro-10-(o-chlorophenyl)- 1 ,2,3,4-tetrahydro-2-methylbenzo [b][ 1,6]naphthyr1'dine (31.2 g., 91.0 percent), m.p. 156.6l57.5 C.

By the procedure of Example IV, the above prepared base is converted to 8-chloro-lO-(o-chlorophenyl)-1,2,3,4- tetrahydro-2-methylbenzo [b] 1,6] naphthyridine hydrochloride, m.p. 275279 C. (uncorr.

Anal. Calcd. for C H,,Cl N C, 60.11; H, 4.51; Cl, 28.01; N, 7.37.

Found: C, 60.40; H, 4.41; CI, 27.2; N, 7.65.

EXAMPLE XII Th procedure of Example X1 is repeated to prepare the following tetrahydrobenzo [b][ 1,6]naphthyridine hydrochlorides from the corresponding starting compounds: l-(p-ethylphenyl)2-ethylsulfonyl-1,2,3,4- tetrahydrobenzo[bl[ l .6] naphthyridine hydrochloride;

7-butoxy- 1 ,2,3,4-tetrahydro- 1 0-(p-methoxyphenyl)-2- phenylsulfonylbenzo[b][ 1,6]naphthyridine hydrochloride;

1,2,3 ,4-tetrahydro-2-methoxyethyl- 1 0-phenylbenzo[b] |,6]naphthyridine hydrochloride;

1 ,2,3 ,4-tetrahydro-2-dimethylaminoethyl- 1 O-phenylbenzo[b][ 1,6]naphthyridine hydrochloride; and

7-bromo- 1 0-( p-ethoxyphenyl 1 ,2,3,4-tetrahydrobenzo [b][ 1,6]naphthyridine hydrochloride.

EXAMPLE Xlll A mixture of 2-aminobenzophenone (5.0 g., 0.0368 m.), polyphosphoric acid (350 g.) and 1-benzyl-4-piperidone (5.66 g., 0.050 m.) is heated to reflux overnight. The cooled reaction mixture is poured with stirring into a mixture of ice water. The resulting solution is filtered to remove a small amount of insoluble solid, then basified with 50 percent potassium hydroxide (100 cc.). The product separates as a crystalline solid, which is collected, washed thoroughly with water, and dried. In this manner, is obtained 2-benzyl-1,2,3,4-tetrahydro- 10-phenylbenzo[b][1,6]naphthyridine which is dissolved in ether and treated with dry hydrogen chloride to yield the corresponding dihydrochloride salt.

In a similar manner, 2-benzy1-1,2,3,4-tetrahydro-IO-phenylbenzo[b][1,6]naphthyridine hydrobromide and 1,2,3,4- tetrahydro-Z-methoxypropyl-10-phenylbenzo[b][ 1,6]naphthyridine hydrochloride are synthesized.

EXAMPLE XlV 2-Amino-5-chlorobenzophenone (1 1.58 g., 0.050 m.), polyphosphoric acid (330 g.), and 2,2,6,6-tetramethyl-4- piperidone (7.76 g., 0.050 m.) are admixed, heated gradually to 140 C. with stirring, and maintained at that temperature for 3 hours. The reaction mixture is cooled to 100 C. and is poured with stirring into a mixture of ice and water (600 g.). The resulting solution is filtered to remove a small amount of insoluble solid, then basified with 25 percent potassium hydroxide (240 cc.). The crude product separates as a crystalline solid which is filtered, washed and dried, (9.1 g.). Upon recrystallization from hexane, there is obtained colorless prisms of 8-chlorol ,2,3,4-tetrahydrol 1 ,3,3-tetramethyl-l0- phenylbenzo [b][1,6]naphthyridine (4.30 g., 24.5 percent m.p. 176178 C. (uncorr.).

Ana1.Ca1cd.for C H C1N C, 75.32; H, 5.72; N, 8.37.

Found: C, 75.38; H, 5.56; N, 8.44.

The above prepared base is converted by the procedure of Example 1V to colorless prisms of the corresponding hydrochloride, m.p. 312 C.

Anal. Calcd. for c H Cl N z C, 68.22; H, 6.25; Cl, 18.30; N, 7.23.

Found: C, 68.00; H, 6.44; CI, 18.0; N, 6.95.

EXAMPLE XV 2-Amino-2,5-dichlorobenzophenone (13.31 g., 0.050 m.) is reacted with 2,2,6,6-tetramethyl-4-piperidone (7.76 g., 0.050 m.) by the procedure described in Example XlV to produce colorless prisms of 8-chloro-l0-(o-chlorophenyl)- l,2,3,4-tetrahydro-1,1,3,3-tetramethylbenzo [b][ 1,6]naphthyridine, m.p. l94-195 C. (uncorr.

Anal. Calcd for C H CI N C, 68.57; H, 5.76; Cl, 18.40; N, 7.27.

Found: C, 68.63; N, 5.81;Cl, 18.1; N, 7.07.

The above prepared base is converted to the hydrochloride in a manner similar to that of Example 1V and colorless crystals thereof are obtained from 95 percent ethanol, mp. 310 C. (uncorr.).

Anal. Calcd. for C H cl N C, 62.64; H, 5.49; Cl, 25.22; N, 6.64.

Found: C, 62.60; H, 5.56; Cl, 25.2; N, 6.75.

EXAMPLE XVl The procedure of Example XIV is again repeated reacting a 2-amino-5-substituted benzophenone with a 2,2,6,6- tetramethyl-4-piperidone to synthesize the following compounds:

8-bromo-l,2,3,4-tetrahydro-l,1,3,3-tetramethyl-10-pheny1- 2-propoxyethylbenzo[b][ 1 ,6]naphthyridine;

2-(p-bromophenyl)-1,2,3,4-tetrahydro-l0-(p-iodophenyl)- l,1,3,3-tetramethylbenzo[b][ 1,6]naphthyridine;

8-chloro-1,2,3,4-tetrahydro-l,1,3,3-pentamethyl-10-phenylbenzo[b][ 1,6]naphthyridine; and

8-chloro-1,2,3,4-tetrahydro-1,1,3,3-tetramethyl-l0-(pmethoxyphenyl)benzo[b[ 1 ,6]naphthyridine.

EXAMPLE XVII 2-Amino-5-chlorobenzophenone (16.62 g., 0.0718 m.), polyphosphoric acid (500 g.) and tropinone (10.0 g., 0.0718 m.) are mixed, heated to C. with stirring, and maintained at that temperature for one-half hour. Thereafter, upon cooling the reaction mixture is poured into a mixture of ice and water (500 g.) with stirring. The solution is filtered, basified with 10N sodium hydroxide, and the resulting solid is separated by filtration (21.3 g., 88.8%), m.p. l75-l77 C. (uncorr.). Upon recrystallization from a benzene-hexane mixture, there is obtained colorless prisms of 8-chloro-l,2,3,4- tetrahydro-Z-methyl- 1 O-phenyl- 1 ,3-ethanobenzo [b 1,6]naphthyridine (13.6 g., 56.7 percent, m.p. l90191 C. (uncorr.).

Anal. Calcd. for C H, C1N C, 75.32; H, 5.72; N, 8.37.

Found: C, 75.38; H, 5.56; N, 8.44.

The corresponding hydrochloride is prepared as colorless crystals from ethanol, mp. 310 C.

Anal. Calcd. for C H Cl- N C, 67.93; H, 5.43; Cl, 19.10; N, 7.54.

Found: C, 67.65; H, 5.33; Cl, 18.9; N, 7.55.

EXAMPLE XVIII A mixture of 0.0346 m of 2-amino-3-chlorobenzophenone, 0.0346 m of l-benzoyl-4-piperidone hydrochloride and 35 ml of trifluoroacetic acid is refluxed for three hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is then extracted with a 20 percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product. Recrystallization of the free base from hexane affords a white EXAMPLE XIX Freshly distilled ethyl chloroformate (2.9 ml., 0.030 m.) in dry benzene (30 ml.) is added dropwise with stirring to a solution of 8-chloro-l,2,3,4-tetrahydro-2-methyl-lO-phenylbenzo[b][1,6]naphthyridine (6.8 g., 0.02 mole) in dry benzene (70 ml.). The solution is refluxed for 24 hours and then cooled and filtered. The filtrate is washed with water, dried and evaporated giving a solid (2.5 g.), m.p. 146-9 C. Recrystallization from cyclohexane affords 8-chloro-2-ethoxycarbonyl-l,2,3,4-tetrahydro-10-phenylbenzo[b][ 1,6] naphthyridine, as a crystalline solid 1.8 g. m.p. l53,-4 C.

Anal. Calcd. for C ,H, ClN,O C, 68.76; H, 5.22; N, 7.63; CI, 9.66.

Found: C, 68.93; H, 4.96; N, 7.77; CI, 9.7.

Similarly, 2-butoxycarbonyl-1,2,3,4-tetrahydro-l0-phenylbenzo[b][ 1 ,6]naphthyridine is produced.

EXAMPLE XX A solution of 8-chloro-2-ethoxycarbonyl- 1 ,2,3 ,4- tetrahydrol -phenylbenzo[b][ 1,6]naphthyridine (0.7 g., 0.0019 m.), as prepared above, in potassium hydroxide g.), n-propyl alcohol (20 ml.) and water (0.5 ml.) is refluxed for three hours. The solution is evaporated and the residue dissolved in benzene followed by extraction with water. Evaporation of the benzene solution gives the product (0.5 g., 92 percent m.p. l303 C.). Recrystallization from cyclohexanehexane affords yellow crystals of 8-chloro-l,2,3,4-tetrahydrol0-phenylbenzo[b][1,6]naphthyridine, m.p. l37-9 C.

Anal. Calcd. for C H ClN C, 73.34; H, 5.13; N, 9.51; CI, 12.03.

Found: C, 72.75; H, 5.09; N, 9.44; Cl, 11.7.

Similar treatment of the above prepared 2-butoxycarbonyll ,2,3,4-tetrahydrol 0-phenylbenzo]b][ l ,6]naphthyridine affords l,2,3,4-tetrahydro-l0-phenylbenzo[b][ 1,6 ]naphthyridine.

EXAMPLE XXI To a solution of 8-chloro-1,2,3,4-tetrahydro-lO-phenylbenzo[b][1,6]naphthyridine (2.0 g., 0.00683 m.) in tetrahydrofuran (20 ml.) and percent aqueous sodium hydroxide (10 ml.) at 0 C. is slowly added chloroacetyl chloride (0.6 ml.,0.08 m.) and stirred for 45 minutes. Water (100 ml.) is added and the product collected (2.3 g), m.p. l502 C. Recrystallization from benzene-hexane affords 8- chloro-2-chloroacetyll ,2,3,4-tetrahydrol 0-phenylbenzo[b] 1,6]naphthyridine as yellow crystals, m.p. 158-9 C.

Anal. Calcd. for C H Cl N O: C, 64.70; H, 4.35; N, 7.55; CI, 19.5.

Found: C, 64,98; H, 4.23; N, 7.70; CI, 19.0.

Repeating the aforesaid procedure to react an appropriate tetrahydrobenzonaphthyridine with a haloalkanoyl chloride, the following compounds are prepared:

l0-phenyl-2-( 3-bromopropionyl l ,2,3,4-tetrahydrobenzo[b][ 1,6]naphthyridine;

7-methoxy-2-iodoacetyll ,2 ,3,4-tetrahydrol O-phenylbenzo[b][ 1,6]naphthyridine; and v 2-fluoroacetyl-l,2,3,4-tetrahydro-10-phenylbenzo[b] 1,6]naphthyridine.

EXAMPLE XXII A solution of 8-chloro-1,2,3,4-tetrahydro-10-phenylbenzo[b][1,6]naphthyridine (5.0 g., 0.017 m.), glycidol (1.26 g., 0.017 m.) and xylene (40 ml.) is refluxed for fifteen hours. Evaporation of the solution gives an oil which aflord a solid upon extraction with cyclohexane. Recrystallization from ethyl acetate afl'ords 8-chloro-2-(2,3-dihydroxypropyl)- 1,2,3,4tetrahydrol 0-phenylbenzo[b][ 1,6]naphthyridine, light yellow solid, m.p. l545 C.

Anal. Calcd for c,,H,,c1N,o,: C, 68.37; H, 5.74; N, 7.58; CI, 9.62.

Found: C, 68.10; H, 5.82; N, 7.81; CI, 9.4.

In a similar manner, 8-bromo-2-(2,3-dihydroxy-butyl)- 1 ,2,3,4-tetrahydrol 0-phenylbenzo[ b][ l ,6 ]naphthyridine is synthesized.

EXAMPLE XXIII A mixture of 8-chloro-l,2,3,4-tetrahydro-10-phenylbenzo[b][ 1,6]naphthyridine (8.5 g., 0.029 m.) and l-guanyl- 3,5-dimethylpyrazole nitrate (2.9 g., 0.0144 m.) is ground together and stirred under nitrogen at 160 C. for 2 hours. Upon cooling the gum is heated with ethyl acetate (30 ml.) and the product filtered after cooling (4.7 g., 0.01 17 m., 82 percent). Recrystallization from ethanol-water affords white crystals of 2-amidino-8-chloro-l ,2,3,4-tetrahydrol O-phenylbenzo[b][ 1,6]naphthyridine nitrate, m.p. 270 1 C. decomp.

Anal. Calcd. for C H ClN, HNO C, 57.07; H, 4.34; N, 17.52; Cl, 8.87.

Found: C, 57.14; H, 4.50; N, 17.34; CI, 8.8.

EXAMPLE XXIV A solution of 8-chloro-2-chloroacetyl-1,2,3,4-tetrahydrol0-phenylbenzo[b][1,6]naphthyridine (6.0 g., 0.161 m.), diethylamino (3.4 ml., 0.0322 m.), anhydrous potassium carbonate (4.45 g.) and dimethyl forrnamide (50 ml.) is heated at 55 C. for 3 hours. Filtration and evaporation of the solvent gives a gum. This is dissolved in methylene chloride, extracted with water and evaporated, giving an oil. The oil is dissolved in a 2 percent hydrochloric acid solution and filtered. The filtrate is made alkaline, extracted with methylene chloride and evaporated giving a gum. The crude base is added to a hot solution of p-toluene sulphonic acid in tetrahydrofuran. A solid is obtained and recrystallization from tetrahydrofuranethanol affords white crystals of 8-chloro-2-( 2- diethylaminoacetyl)- l ,2,3,4-tetrahydro- 1 0-phenylbenzo[ b][1,6]naphthyridine di-p-toluene sulfonate, m.p. 2256 C. decomp.

Anal. Calcd. for C H ClN 0 2C H 0 S: C, 60.67; H, 5.63; N, 5.59; Cl, 4.7.

Found: C, 60.70; H, 5.34; N, 5.74; C], 4.8.

In a similar manner, the following compounds are prepared:

1 ,2,3,4-tetrahydro-2-(3-dimethylaminopropionyl)-1 O-(ptolyl)benzo[b][ 1,6]naphthyridine dihydrochloride; and

1,2,3,4-tetrahydro-7-methyl-10-phenyl-2-(4- dipropylaminobutyryl)benzo[b][ 1,6]naphthyridine toluene sulfonate.

di-p- EXAMPLE XXV To a solution of 8-chloro-1,2,3,4-tetrahydro-IO-phenylbenzo[b][1,6]naphthyridine (6.0 g., 0.0204 m.), triethylamine (3.34 ml., 0.024 m.) and tetrahydrofuran ml.) at 0 C. is slowly added dichloroacetyl chloride (2.02 ml., 0.02] m.) and the mixture is stirred for 2 hours. Evaporation of the tetrahydrofuran gives a solid which is slurried with chloroform and water. The water is separated and the product recrystallized from benzene affording white crystals of 8- chloro-2-dichloroacetyl- 1 ,2,3,4-tetrahydrol O-phenylbenzo[b][ 1,6]naphthyn'dine, m.p. 2156 C.

Ana]. Calcd. for C H, Cl N 0: C, 59.20; H, 3.72; N, 6.91; C1, 26.2.

Found: C, 59.70; H, 3.92; N, 6.53; Cl, 25.8.

EXAMPLE XXVI A mixture of 0.0346 m. of 2-amino-3-chlorobenzophenone, 0.0346 m. of 1-(3-dimethylaminopropyl-4-piperidone hydrochloride and 35 ml. of trifluoroacetic acid is refluxed for 3 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a 20 percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product which is converted to the maleate salt by interaction with maleic acid in acetone. Addition of ethyl ether precipitates the salt which is recrystallized from acetonitrile to yield 8-chloro-2-(3-dimethylaminopropyl)-1,2,3,4- tetrahydro- 1 0-phenylbenzo[b] l ,6lnaphthyridine dimaleate, m.p. 1734C. decomp.

Anal. Calcd for C, ',H ,,CIN; 2C 411,0 C, 60.83; H, 5.60; N, 6.86; Cl, 5.79.

Found: C, 60.67; H, 5.76; N, 6.80; Cl, 5.8.

EXAMPLE XXVII A mixture of(0.0346 m.) 2-amino-3,5- dichlorobenzophenone, (0.0346 in.) of 4-benzylpiperidone hydrochloride and and 35 ml. of trifluroacetic acid is refluxed for 3 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product as a brown gummy solid, which is collected, washed thoroughly with water, reacted with dry hydrogen chloride by the procedure of Example [V and recrystallized from n-propyl alcohol and water to afford yellow crystals of 2-benzyl-6,8- dichloro-l ,2,3,4-tetrahydro-10-phenylbenzo[b][ 1,6] naphthyridine dihydrochloride, m.p. 272-3 C. decomp.

Anal. Calcd for C H N C1 HCl: C, 65.87; H, 4.64; N, 6.14; Cl, 23.3.

Found: C, 65.71; H, 4.69; N, 5.98; Cl, 23.0.

EXAMPLE XXVlll Repeating the procedure of Example XXVI] to react an appropriate 2-aminobenzophenone and a 4-piperidone, the hereinafter listed tetrahydronaphthyridines are obtained:

8-ethyl-2-(2,3-dihydroxypropyl)-l ,2,3,4-tetrahydro-10- phenylbenzo[b][ l ,6]naphthyridine;

8-bromo-1 ,2,3,4-tetrahydro-2-methoxycarbonyl-10-phenylbenzo[b][ 1 ,6]naphthyridine;

10-phenyl-2-chloroacetyl-1,2,3,4-tetrahydrobenzo[b 1,6 ]naphthyridine; 5

Z-amidinol ,2,3,4-tetrahydrol 0-phenyl-7-propylbenzo[b l ,6 ]naphthyridine;

8-bromo-2-(2-diethylaminoacetyl)-1,2,3 ,4-tetrahydrol 0- phenylbenzo[b][ l,6]naphthyridine;

2-(2,2-dichloroacetyl)-1,2,3 ,4-tetrahydrol 0-( ptolyl)benzo[b][ l,6]naphthyridine;

10-(p-bromophenyl)-1,2,3,4-tetrahydro-2,7-dimethyl-8- methylsulfonylbenzo[b][ l,6]naphthyridine;

2-ethyl-l ,2,3,4-tetrahydro-10-phenyl-8-sulfamoylbenzo[b 1,6 ]naphthyridine; 5

l0-phenyl-7-chlorol ,2,3,4-tetrahydro-8-sulfamoylbenzo[b l,6]naphthyridine;

7-carbamoyl-8-trifluoromethyl-1,2,3,4-tetrahydro10-phenylbenzo[b][ 1 ,6]naphthyridine;

6,9-diethoxy-Z-ethoxycarbonyll ,2,3,4-tetrahydrol0-(ppropylphenyl)benzo[b][ l,6]naphthyridine;

8-trifluromethyl- 1 ,2,3 ,4-tetrahydro-2-methyl- 1 O-phenylbenzo[b][ 1,6]naphthyridine 7,8-diethyll ,2,3,4-tetrahydro-2-methoxycarbonyl-10- phenylben2o[ b][ l,6]naphthyridine;.

7,9-dichloro-2-ethoxycarbonyl-l ,2,3,4-tetrahydro-10-(ptolyl)benzo[b][ l,6]naphthyridine;

10-phenyl-1,2,3 ,4-tetrahydro-7,8-dimethoxy-2-methoxycarbonylbenzo[b][ l,6]naphthyridine;

8-ethylthio- 1 ,2,3,4-tetrahydro-2-(2,3-dihydroxypropyl)-l0- phenylbenzo[b][ l ,6]naphthyridine;

2-ethoxycarbonyl-2,7-diethy1- l ,2,3,4-tetrahydro-8- methylthiol 0-phenylbenzo[b][ l,6]naphthyridine; and

l ,2,3 ,4-tetrahydro-10-phenyl-2-propyl-8-propylsulfonylbenzo[b][ l ,6]naphthyridine. 75

EXAMPLE XXIX Employing the procedure of Example 1X upon the tetrahydrobenzonaphthyridines of ExampleXXVlll, the following octahydrobenzonaphthyridines are prepared:

8-ethyl-2-(2,3-dihydroxypropyl)-1,2,3,4,4a,5,l0,10a-octahydro-10-phenylbenzo[b][ l,6]naphthyridine;

8-bromo-2-methoxycarbonyl-1,2,3,4,4a,5,10,10a-octahydro-10-phenylbenzo[b][ l,6]naphthyridine;

10-phenyl-Z-chloroacetyl-1,2,3,4,4a,5,10,10a-octahydrobenzo[b][ 1 ,6]naphthyridine;

2-amidino-1,2,3,4,4a,5,10,10a-octahydrobenzo-IO-phenyl- 7-propylbenzo[ b] 1 ,6]naphthyridine;

8-bromo-2-(2-diethylaminoacetyl)-l,2,3,4,4a,5,10,10a-octahydro-10-phenylbenzo[b][ 1 ,6]naphthyridine;

2-(2,2-dichloroacetyl)-1,2,3,4,4a,5,10,10a-octahydro-10- p-tolyl)benzo[b][ l,6]naphthyridine;

10-(p-bromopheny1)-l,2,3,4,4a,5,10,10a-octahydro-2,7- dimethyl-8-methylsulfonylbenzo[b][ 1 ,6]naphthyridine; 2-ethyl-1,2,3,4,4a,5,10,l0a-octahydro-10-phenyl-8- sulfamoylbenzo[b][ 1 ,6]naphthyridine;

l0-phenyl-7-chloro-1,2,3,4,4a,5,10,10a-octahydro-8- sulfamoylbenzo[b][ l,6]naphthyridine;

7-carbamoyl-8-trif1uoromethyl-l,2,3,4,4a,5,10,10a-octahydrol 0-phenylbenzo[b][ 1 ,6]naphthyridine;

6,9-diethoxy-2-ethoxycarbonyl-l,2,3,4,4a,5,10,10a-octahydrol0-(p-propylpheny1)benzo[b][ l ,6]naphthyridine;

8-trifluoromethyll ,2,3,4,4a,5, l0, 1 Oa-octahydro-Z-methyll0-phenylbenzo[b][ 1,6 ]naphthyridine;

7,8-diethyl-l ,2,3,4,4a,5,10,lOa-octahydro-Z-methoxycarbonyll0-phenylbenzo[b][ l,6]naphthyridine;

7,9-dichloro-2-ethoxycarbonyl-1,2,3,4,4a,5,l0,10a-octahydrol0-(p-toly1)benzo[b] 1 ,6lnaphthyridine;

10-phenyl-1,2,3,4,4a,5,10,10a-octahydro-7,8-dimethoxy-2- methoxycarbonylbenzo[b][ l,6]naphthyridine;

8-ethylthio-1,2,3,4,4a,5,10,l0a-octahydro-2-(2,3-dihydroxypropyl)- l 0-phenylbenzo[b][ l,6]naphthyridine;

2-ethoxycarbonyl-2,7-diethy1-l,2,3,4,4a,5,10,10a-octahydro-8-methylthio-l0-phenylbenzo[b][ l,6]naphthyridine; and

1,2,3,4,4a,5,10,10a-octahydro-10-phenyl-2-propyl-8- propylsulfonylbenzo[b][ l,6]naphthyridine.

EXAMPLE XXX To a solution of 252.0 g. (4.5 m.) of potassium hydroxide (assay 85 percent) in 500 ml. of methanol there are added with stirring and cooling in an ice bath 41.2 g. (0.28 m.) of pmethoxyphenylacetonitrile and a solution of 50.0 g. (0.26 m.) of 3,4-dichloronitrobenzene in 400 ml. of methanol. The mixture is stirred for 4 hours at 0-5 C. and then 3000 ml. of water is added with mining. The preciptiate is isolated by filtration, dissolved in methylene chloride, washed with water, dried and evaporated. The residue is recrystallized from benzene-hexane giving 23 g. (30 percent) of 5,6-dichloro-3- (p-methoxyphenyl)-2,1-benzisoxazole. A second recrystallization of the product from n-propanol gives the pure crystalline solid, m.p. 156-8 C. (uncorr.

Anal. Calcd for C H CI NO C, 57.17; H, 3.1 1; N, 4.76; Cl, 24.11.

Found: C, 57.37; H, 3.16; N, 5.04; Cl, 24.8.

A mixture of 2.0 g. (0.0682 m.) of the above prepared 5,6- dichloro-3-( p-methoxyphenyl)-2,l-benzisoxazole, 0.1 g. of 10 percent palladium on charcoal and ml. of ethyl acetate in a sealed vessel is treated with hydrogen gas at l-2 atm. and heated to 55 C. for 5 hours. The solution is filtered and evaporated giving 1.5 g (74 percent) of 2-amino-4,5-dichloro- 4 methoxybenzophenone which is recrystallized from absolute ethanol to afiord the pure crystalline solid, m.p. 169-170 C. (uncorr.

Anal. Calcd for C H CI NO C, 56.76; H, 3.75; N, 4.73; Cl, 23.94.

Found: C, 56.72; H, 3.69; N, 4.67; Cl, 23.8.

A mixture of 5.0 g (0.168 m.) of 2-amino-4,5-dichloro-4'- methoxybenzophenone 3.5 g (0.185 m.) of l-benzyl-4- piperidone hydrochloride and 35 ml. of trifluoroacetic acid is refluxed for 3 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a 20 percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product which is recrystallized from ethylacetate to afford 4.5 g (60 percent) of product. A second recrystallization from tetrahydrofuran gives 2-benzyl-7,8-dichloro-1,2,3,4 tetrahydro-10-(p-methoxyphenyl)benzo[b][ l ,6] naphthyridine as crystalline solid, mp. 195"-6 C. (uncorr.).

Anal. Calcd for C H Cl N m C, 69.49; H, 4.71; N, 6.24.

Found: C, 69.50 H, 4,89; N, 6.30.

Employing the procedure of Example IX, the above product is converted to 2-benzyl-7,8-dichloro-l,2,3,4,4a,5,10,10a-octahydro- 1 p-methoxyphenyl )benzo b] l ,6 ]naphthyridine.

EXAMPLE XXXl 2-Amino-5-chloro-3'-sulfamylbenzophenone (3.0 g., 0.00965 m.) prepared by the procedure described in copend ing U.S. Pat. No. 3,516,992 ofJune 23, 1970 is reacted with lbenzyl-4-piperidone (1.82 g., 0.00965 m.) in the manner which is described in Example XXX. Several recrystallizations of the free base from benzene affords m-(2-benzyl-8-chloro- 1 ,2,3,4-tetrahydrol 0-benzo[b][ 1,6]naphthyridinyl)benzenesulfonamide as a crystalline solid, mp. 189l93 C. (uncorr.).

Anal. Calcd for C ,,H C1N 0 S: C, 64.72; H. 4.78; N, 9.06; CI, 7.64.

Found: C, 64.67; H, 5.00; N, 9.15; Cl, 7.7.

When the above product is hydrogenated by the process of Example 1X, there is obtained m-(2-benzyl-8-chloro-l,2,3,4,4 a,5,l0,IOa-octahydro-10-benzo[b][ 1,6]naphthyridinyl )benzenesulfonamide.

EXAMPLE XXXll A mixture of 7.0 g (0.03 m) of 2-amino-3-chlorobenzophenone, 5.5 g (0.03 m) of 1-benzyl-4-piperidone hydrochloride and 35 ml. of trifluoroacetic acid is refluxed for 3 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a 20 percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product as a brown oil. The hydrochloride salt is prepared in a methylene chloride solvent. Evaporation of the solvent and recrystallization of the residue from acetonitrile gives 2- henzyl-6-chlorol ,2,3,4-tetrahydrol 0-phenylbenzo[b][ 1,6] naphthyridine hydrochloride as a crystalline solid (7.0 g, 59 percent) m.p. 24l-2C. (uncorr.).

Anal. Calcd for C ,H ,ClN -HCl: C, 71.25; H, 5.27; N, 6.65; C1, 16.8.

Found: C, 70.92; H, 5.15; N, 6.85; CI, 16.9.

1n the same manner, reacting the following 2- aminobenzophenones and 4-piperidones the hereinafter products are obtained:

2-Amino-5,4'-dichlorobenzophenone (3.8 g, 0.014 rn.) is reacted with l-benzyl-4-piperidone (2.69 g, 0.014 m.). The free base is extracted with hexane giving 2.8 g. (47 percent) or product as a crystalline solid which is recrystallized twice from cyclohexane to afford 2-benzy1-8-chloro-10-(p chlorophenyl)-1 ,2,3 ,4-tetrahydrobenzo[b 1,6]naphthyridine, m.p. l45-6 C. (uncorr.).

Anal. Calcd for C ,,H Cl N C, 71.61; H, 4.81;N, 6.68; Cl, 16.91.

Found: C, 71.84; H, 5.02; N, 6.56; Cl, 16.6.

2-Amino-5-chloro-4-methoxybenzophenone (5.0 g., 0.019 m.) is reacted with 1-benzyl-4-piperidone (3.6 g., 0.019 m.). Recrystallization of the free base from cyclohexane affords 4.0 g. (51 percent) of crude product which is recrystallized twice from benzene-hexane to yield 2-benzyl-8-chloro-l,2,3,4 -tctrahydrol O-(p-methoxyphenyl)benzo[b][ 1,6] naphthyridine as a crystalline solid, mp. l76-7 C. (uncorr.

Anal. Calcd for Cg HgaClNgOl C, 75.26; H, 5.59; N, 6.92; CI, 8.54.

Found: C, 75.30; H, 5.48; N, 6.58; C], 8.45.

2-Amino-4'-methylbenzophenone (6.0 g, 0.028 m.) is reacted with 2,2,6,6-tetramethyl-4-piperidone hydrochloride (5 .5 g., 0.028 m. Recrystallization of the free base from hexane gives 1,2,3 ,4-tetrahydrol 1,3 ,3-tetramethyll 0-( D- toly)benzo[b][l ,6] naphthyridine as a crystalline solid. mp.

Anal. Calcd for C H N C, 83.58; H, 7.93; N, 8.49. Found: C, 83.23; H, 7.73; N, 8.34.

Employing the procedure of Example 1X, the above products are converted to the following:

2-benzy1-6-chloro- 1 ,2,3 ,4,4a,5 l 0, l 0a-octahydrol O-phen ylbenz0[b][ 1 ,6]naphthyridine;

2-benzyl-8-chloro-l0-(p-ch1orophenyl)-l ,2,3,4,4a,5,l0, 10 a-octahydrobenzo[b][ 1,6 naphthyridine;

2-benzyl-8-chloro-1,2,3,4,4a,5 10,10a-octahydro-l0-(pmethoxyphenyl)benzo[b][ 1,6]naphthyridine; and

l,2,3,4,4a,5,10,10a-octahydro-1,1,3,3-tetramethyl-l0-(ptolyl )benzo[b][ 1,6]naphthyridine.

EXAMPLE XXXlll C. (uncorr.

Anal. Calcd for C H ClN- C, 75.30; H, 6.61; N, 7.98.

Found: C, 75.14; H, 6.66; N, 7.97.

Similarly, 2-amino4,5,4-trimethoxybenzophenone (5.0 g., 0.0174 m.) is reacted with 2,2,6,6-tetramethyl-piperidone hydrochloride (3.34 g., 0.0174 m.). The free base is dissolved in absolute ethanol, filtered and the solvent, evaporated. Recrystallization of the residue from cyclohexane affords 7,8- dimethoxy-l ,2,3,4-tetrahydro-1,1,3,3-tetramethyl-l0-(pmethoxyphenyl)benzo[b[1,6]naphthyridine as a crystalline solid, 2.7 g. (37 percent), m.p. 179182 C. (uncorr.

Anal. Calcd for C H N O C, 73.86; H, 7.44; N, 6.89.

Found: C, 73.73; H, 7.58; N, 6.63.

When the above products are hydrogenated by the process of Example 1X, the following compounds are obtained: 6- chloro-l,2,3,4,4a,5,10,10a-octahydro-l,1,3,3-tetramethyl-10- phenylbenzo[b][ 1,6]naphthyridine; and 7,8-dimethoxy- 1,2,3,4,4a,5,10,l01,l,3,3-tetra.rnethyl-10-(pmethoxyphenyl)benzo[b][ l ,6]naphthyridine.

EXAMPLE XXXIV A Grignard reagent prepared from 66.8 (0.41 m.) of 2- bromothiophene and 11.4 g. (0.45 m.) of magnesium in 200 ml. of ether is slowly added over a period of one-half hour to a solution of 80.0 g. (0.41 m.) of 2-methyl-7-chloro-4H-3,lbenzoxazin-4-one, prepared as described in Ind. .1. Pharm. by Somasekhara et a1. 27, 12-13 (1965), in 575 ml. of benzene keeping the temperature at 15-20 C. during the addition. The reaction mixture is then stirred for 45 minutes at 50-60 C. After cooling to 20 C., the complex is decomposed by the slow addition of 350 ml. of 2 N hydrochloric acid. The organic layer is separated, washed with dilute sodium hydroxide, water, dried over sodium sulfate and evaporated to dryness. The product is triturated with absolute ethanol and recrystallized from cyclohexane giving 2-acetamido-4-chlorophenyl-2 -thieny1 ketone as a crystalline solid, mp. l00-l01 C. (uncorn).

Anal. Calcd for C, H, ClNO S: C, 55.80; H, 3.60; N, 5.00; CI, 12.67; 5, 11.46.

Found: C, 55.76;H, 3.27; N,5.00;Cl, 12.7; S, 11.1.

A solution of 59.4 g. (0.212 m.) of 2-acetamido4- chlorophenyl-2-thienyl ketone in 1,400 ml. of ethanol and 600 ml. 6 N hydrochloric acid is refluxed for 4 hours. The residue obtained, after evaporation of the solvent, is basified with sodium carbonate and extracted with methylene chloride. The methylene chloride solution is dried over sodium sulfate and evaporated leaving 39 g. of solid. Recrystallization of the product from cyclohexane gives 2-amino4- chlorophenyl-2'-thienyl ketone, m.p. 79-8 1 C., (uncorr.).

Anal. Calcd for C H CINOS: C, 55.55; H, 3.39; N, 5.89; Cl, 14.92; S, 13.49.

Found: C, 55.78; H, 3.19; N, 5.83;Cl, 14.9; S, 13.4.

A mixture of 2-acetamido-4-chlorophenyl'2-thienyl ketone (0.212 m.), l-methyl-4-piperidone (0.021 m.) and 40 ml. of glacial acetic acid is refluxed for 4 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a 20 percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product. Trituration of the free base with hexane gives 7-chloro-1,2,3,4-

tetrahydro-2-methyll 2-thieny1)benzo[b][ 1,6 ]naphthyridine as a crystalline solid (4.8 g, 73 percent) m.p. l413 C. (uncorr.).

Anal. Calcd for C, H, ClN S: C, 64.86; H, 4.80; N, 9.89.

Found: C, 65.16; H, 4.91;N, 8.92.

When the above compound is hydrogenated by the procedure of Example 1X, there is afforded 7-chloro- 1 ,2,3,4,4a,5,10,102-methyll0-(2-thienyl)benzo[b]1,6]naphthyridine.

EXAMPLE XXXV Following the procedure described in Example XXXIV, 8.33 g (0.41 m.) of 4-bromothioanisole, 11.4 g (0.45 m.) of magnesium and 80.0 g (0.41 m) of 2-methyl-7-chloro-4H-3, 1- benzoxazin- 4-one produce 5'-chloro-2-(pmethylthiobenzoyl) acetanilide. Recrystallization of the product from methanol affords a crystalline solid, wt. 31.0 g (25 percent) m.p. 857 C. (uncorr.).

Anal. Calcd for C H CINO S: C, 60.09; H, 4.41; N, 4.38.

Found: C, 59.94; H, 4.35; N, 4.47.

Following the procedure described in Example XXXlV, 26.2 g (0.082 m.) of 5'-chloro-2'-(pmethylthiobenzoyl)acetanilide are hydrolyzed to give 24 g m.p. l 19-23 C. of 2-amino-4-chloro-4'- methylthiobenzophenone. Recrystallization of the product from cyclohexane affords a crystalline solid, mp. l22-4 C. (uncorr.).

Anal. Calcd for C H CINOS: C, 60.52; H, 4.35; N, 5.04.

Found: C, 60.32; H, 4.29; N, 4.89.

A mixture of 5.0 g. (0.018 m.) of 2-amino-4-ch1oro-4'- methylthiobenzophenone, 3.46 g. (0.018 m.) of 2,2,6,6- tetramethyl-4-piperidone hydrochloride and 35 ml. of trifluoroacetic acid is refluxed for 3 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving the crude product. Recrystallization of the free base from hexane affords 7-chloro-l ,2,3,4- tetrahydro-l,1,3,3-tetramethyl-IO-(p-methylthiophenyl) benzo[b][bh1,6]naphthyridine as a crystalline solid 4.8 g. (67

percent), m.p. 1624 C. (uncorr.).

Anal. Calcd for C H ClN s: C, 69.58; H, 6.35; N, 7.06.

Found: C, 69.41; H, 6.05; N, 7.22.

In a similar manner, 10-( p-ethylthiophenyl)-1,2,3,4- tetrahydro-l,1,3,3-tetramethylbenzo[b]1,6]naphthyridine; and 10-( m-butylthiophenyl) l ,2,3,4-tetrahydro-7 methylhenzol bll 1,6 ]naphthyridine are produced.

EXAMPLE xxxvr Following the procedure described in Example XXXlV, 92.3 g (0.41 m.) of 3-bromobenzotrifluon'de, 1 1.4 g (0.45 m.) of magnesium and 80.0 g. (0.41 m.) of 2-methyl-7-chloro-4H- 3,1-benzoxazin-4-one produce 36 g. (26 percent) of 5'- chloro-2'-(m-a,a,a-trifluorotoluoyl)acetanilide, m.p. -95 C., which is recrystallized from hexane, m.p. 86-8 C. (uncorr.).

Anal. Calcd for C H ClF NO z C, 56.24; H, 3.24; N, 4.10.

Found: C, 56.16; H, 3.01; N, 3.91.

Following the procedure described in Example XXXlV, 21.5 g. (0.063 m.) of 5-chloro-2'-(m-a,a,a-trifluorotoluoyl) acetanilide are hydrolyzed to give 18 g., m.p. 85-90 C., of 2- amino-4-chloro-3-trifluoromethylbenzophenone. Recrystallization of the product from hexane affords a crystalline solid, mp. 94-6 C. (uncorr.).

Anal. Calcd for C,.,H,,CIF NO: C, 56.10; H, 3.02; N, 4.67.

Found: C, 56.17; H, 2.93; N, 4.49.

2-Amino-4-chloro-3-trifluoromethylbenzophenone (5.0 g, 0.0167 m.) and 2,2,6,6-tetramethyl-4-piperidone hydrochloride (3.2 g, 0.0167 m.) are allowed to react in a manner similar to Example XIV. The solution is poured into ice water and sodium hydroxide added to adjust the pH to 7. The insoluble product is filtered and recrystallized twice from a dimethylformamide-water mixture giving m-( 7-chlorol ,2,3,4-tetrahydro- 1 l ,3,3-tetramethylbenzo[b] l,6]naphthyridin-l0-yl)benzoic acid as a crystalline solid, mp. 3 10 C. (uncorr.).

Anal. Calcd for CzqHzaClNzOg: C, 70.01; H, 5.87; N, 7.09.

Found: C. 69.73; H, 5.58; N, 7.20.

EXAMPLE XXXVll Following the procedure described in Example XXXlV, reacting 15.0 g. (0.095 m.) of bromobenzene, 2.47 g. (0.1 m.) of magnesium and 15.0 g. (0.077 m.) of 2-methyl-7-chloro-4 H-3,l-benzoxazin-4-one produces a yellow oil. Trituration with a 20 percent cyclohexane-hexane solution gives 3.1 g 15 percent yield) of 5'-chloro-2-benzoylacetanilide. Recrystallization of the product from cyclohexane affords a crystalline solid, mp. 889 C. (uncorr.).

Anal. Calcd for C, H, ClNO C, 65.82; H, 4.42; N, 5.1 1.

Found: C, 65.79; H, 4.45; N, 5.23.

The above compound is also prepared by an alternate procedure. To a same quantity of the Grignard reagent as prepared above is added in 5 minutes, 7.3 g (0.04 m.) of anhydrous cadmium chloride and the solution is refluxed for 20 minutes. The diethyl ether is distilled, replaced with 75 ml. of dry benzene and an additional 15 ml. of the solution is distilled. This slurry is added in thirty minutes to a solution of 15.0 g. (0.077 m.) of 2-methyl-7-chloro-4H-3,l-benzoxazin-4- one in .150 ml. of benzene, and then refluxed for 45 minutes. After cooling to 20 C., the complex is decomposed by the slow addition of ml. of 2 N hydrochloric acid. The resulting solid requires fine crushing before extraction with benzene and dilute hydrochloric acid. The organic layer is separated, washed with dilute aqueous sodium hydroxide, water, dried over anhydrous sodium sulfate and concentrated to dryness in vacuo. The residue is triturated with a 20 percent cyclohexane-hexane solution to give 8.3 g. (39 percent yield) of 5- ch1oro-2-benzoylacetanilide. Recrystallization of the product from cyclohexane affords a crystalline solid, mp. 889 C. (uncorr.).

. Following the procedure described in Example XXXlV, 5- chloro-2'-benzoylacetanilide is hydrolyzed to give 2-amino-4- chlorobenzophenone, m.p. 845 C.

2-Amino-4-chlorobenzophenone (5.0 g, 0.0215 m.) is allowed to react with 1-benzy1-4-piperidone (4.25 g., 0.0225 m.) in a manner similar to Example XXXV. Extraction of the free base with hexane gives 4.0 g (48 percent) of the compound as a crystalline solid. Two recrystallizations from cyclohexane affords 2-benzyl-7-chloro-l ,2,3,4-tetrahydrol 0- phenylbenzo[b][1,6]naphthyridine, m.p. 1423 C. (uncorr.).

Anal. Calcd for C H ,ClN C, 78.01; H, 5.50; N, 7.28. Found: C, 77.60; H, 5.28; N, 7.05.

EXAMPLE XXXVIII A mixture of 3.5 g (0.01 m.) of 8chloro-1,2,3,4-tetrahydrol ,1 ,3 ,3-tetramethyll O-phenylbenzo[b][ l ,6 ]naphthyridine, 9.45 ml. (0.025 m.) of formic acid, 0.083 ml. (0.011 m.) of formalin and 75 ml. of isopropyl alcohol is refluxed for 8 hours. The solution is acidified with 2.5 ml. of 12 N hydrochloric acid, evaporated, the solid residue dissolved in water, the solution made alkaline and extracted with a :95- benzenezdiethyl ether mixture. The organic solvent is evaporated and the residue recrystallized from hexane giving 8-chloro-l ,2,3,4-tetrahydrol 1 ,3 ,3-pentamethyl- 1 O-phenylbenzo[b][ l,6]naphthyridine as a crystalline solid, m.p. l756 C. (uncorr.).

Anal. Calcd for C H ClN C, 75.70; H, 6.90; N, 7.68.

Found: C, 75.81; H, 6.58; N, 7.63.

EXAMPLE XXXIX 2-Aminobenzophenone (6.0 g, 0.0305 m.), l-(-phen-ethyl)- 4-piperidone (6.2 g, 0.0305 m.), 0.3 ml. of trifluoro-acetic and 18 ml. of toluene are refluxed for 12 hours over a Dean Stark trap. The solution is evaporated and the residue extracted with hot hexane. Evaporation of the solvent followed by trituration with diethyl ether gives a solid. Recrystallization from diethyl ether afiords 1,2,3,4-tetrahydro-2-phenethyl-IO-phenylbenzo[b][ l,6]naphthyridine as a crystalline solid, m.p. l l3-4 C. (uncorr.).

Anal. Calcd for C H N C, 85.67; H, 6.64; N, 7.69.

Found: C, 86.31; H, 6.56; N, 7.80.

EXAMPLE XL A mixture of 6.0 g. (0.0305 m.) of Z-aminobenzophenone, 5.77 g. (0.0305 m.) of l-benzyl-4-piperidone and 40 ml. of glacial acetic acid is refluxed for 4 hours. The solution is evaporated under vacuum and the residue is dissolved in methylene chloride which is extracted with a 20 percent aqueous potassium hydroxide solution. The methylene chloride solution is washed with water, dried over anhydrous sodisum sulfate and evaporated giving the crude product. Trituration of the free base with hexane gives 9.5 g (87 percent) of a solid. Recrystallization from cyclohexane gives 2-benzyl-l,2,3,4- tetrahydro--phenylbenzo[b][ 1,6 ]naphthyridine as a crystalline solid, m.p. 158-9 C. (uncorr.).

Anal. Calcd for C H N C, 85.69; H, 6.33; N, 8.00.

Found: C, 85.92; H, 6.13; N, 7.93.

EXAMPLE XLl 8-Chloro-l ,2,3 ,4-tetrahydro-2-methyll 0-phenyl-benzo[b ][l,6]naphthyridin (5.0 g., 0.017 m.), 2.37 g. (0.017 m.) of 5,5-dimethyl-1,3cyclohexanedione, 0.05 ml. of trifluoroacetic and 100 ml. of benzene is refluxed for 2 hours over a Dean- Stark trap. The solution is evaporated and the residue crystallized from hot cyclohexane. Recrystallization from benzene affords 3-( 8-chlorol ,2,3 ,4-tetrahydro- 1 O-phenylbenzo [b][ 1,6]naphthyridin-2-yl)-5,S-dimethyl-2-cyclohexen-l-one as a crystalline solid, m.p. 1 14l50 C. (uncorr.).

Anal. Calcd for C H ClN 0: C, 74.88; H, 6.04; N, 6.73.

Found: C, 74.82; H, 6.00; N, 6.70.

EXAMPLE XLII A solution of 4.5 g (0.0266 m) of 2-amino-4,5-dimcthoxybenzaldehyde, 3.0 g (0.0266 m) of l-methyl-4-piperidone, 15 ml of an aqueous 10% sodium hydroxide solution and 200 ml of absolute ethanol is allowed to stir for six days at C. The solution is filtered and hydrogen chloride gas and 500 ml of diethyl ether are added. The hydroscopic salt is dissolved in water, treated with charcoal, filtered and the filtrate made alkaline. The product is filtered, extracted with diethyl ether and recrystallized from water giving 1,2,3,4-tetrahydro-7,8- dimethoxy-10-phenyl-benzo[b][ 1 ,6]naphthyridine as a crystalline solid.

EXAMPLE xun A solution of 7-chloro-1,2,3,4-tetrahydro- 1 1 ,3,3- tetramethyll 0-( p-methylthiophenyl )benzo[ b][ l ,6] naphthyridine (0.0156 m.) in glacial acetic acid (100 ml.) containing platinum oxide (0.3 g.) is hydrogenated at room temperature, and an initial hydrogen pressure of 46.5 psi for a period of 24 hours. The excess acetic acid is distilled in vacuo, the residue dissolved in water, and then basified whereupon the crude product separates. Recrystallization from cyclohexane-hexane affords 7-chloro- 1 ,2,3,4,4a,5, 10, l Oa-octahydro- 1,1,3,3-tetramethyl-l0-(p-methylthiophenyl)benzo[b][ l ,6 ]naphthyridine.

When the above procedure is repeated employing the compounds of Examples XXXV-XLll, the following products are obtained:

10-(p-ethylthiophenyl)-l,2,3,4,4a,5,10,10a-octahydro- 1,1,3,3-tetramethylbenzo[b][ l,6]naphthyridine;

10-(m-butylthiophenyl)-1,2,3,4,4a,5,10,10a-octahydro-7- methylbenzo[b][ l,6]naphthyridine;

m-(7-chloro-1,2,3,4,4a,5,10,10a-octahydro-l 1 ,3,3- tetramethylbenzo[b][ 1,6]naphthyridin-10-yl)benzoic acid;

2-benzyl-7-chloro-1,2,3,4,4a,5,l0,10a-octahydro-l0-phenylbenzo[b][ l,6]naphthyridine;

8-chloro-l ,2,3,4,4a,5,l0, 10a-octahydro-1 ,1 ,2,3,3-pentamethyl- 1 0-phenylbenzo[ b] 1 ,6]naphthyridine;

l,2,3,4,4a,5 ,10,l0a-octahydro-2-phenethyl-10-phenylbenzo[b][ l,6]naphthyridine;

2-benzyl-1,2,3,4,4a,5,l0,10a-octahydro-l0-phenyl-benzo[b 1,6 ]naphthyridine;

3-( 8-chloro-l ,2,3 ,4,4a,5 10,1 Oa-octahydro- 1 O-phenylbenzo [b] 1 ,6]naphthyridin-2-yl )-5 ,S-dimethylcyclohexan- 1 -one; and

l,2,3,4,4a,5, l 0, l Oa-octahydro-7,8-dimethoxy- 1 O-phenylbenzo[b][ l,6]naphthyridine.

EXAMPLE XLIV A mixture of 2-aminobenzonitrile (5.00 g., 0.0423 in.) and l-methyl-4-piperidone (4.80 g., 0.0423 in.) in polyphosphoric acid (105 g.) is gradually heated to 140150 C., and maintained at this temperature for 1 hour. The dark amber reaction mixture is poured with vigorous stirring into cold water (800 ml.). The resultant clear amber solution is decolorized, filtered through Celite, and the clear filtrate basified with percent KOH (ph ca 10). An oil separates which slowly crystallizes. It is collected by filtration, washed with water, airdried; yield is 1.50 g (16.7 percent) m.p. 82.5 C. (uncorr.). The filtrate is extracted with ether (6 X 200 ml.) and the combined extracts successively washed with water, saturated salt solution, filtered through anhydrous sodium sulfate, and the filtrate concentrated in vacuo giving an oil which crystallizes on trituration with pentane; yield is 0.35 g. (3.9 percent) m.p. 84 C. (uncorr.). Total yield of crude product is 1.85 g (20.6 percent) which is directly converted to the dihydrochloride by saturating a tetrahydrofuran solution with dry hydrogen chloride; colorless crystals (1.90 g.), m.p. 301 C. dec. (uncorr.). Recrystallization of the crude dihydrochloride from percent ethanol affords colorless crystals of the desired 10- amino-1,2,3,4-tetrahydro-2-methylbenzo[b][ l ,6 ]naphthyridi ne dihydrochloride (1.10 g.) m.p. 321-322 C. dec. (uncorr.).

Anal. Calcd for C H CI N C, 54.55; H, 5.85; Cl, 24.78; N, 14.68.

Found: C, 54.73; H, 5.85; Cl, 24.2; N, 14.79.

In a similar manner, IO-amino-Z-ethyl-l ,2,3,4-tetrahydro-8 methy1benzo[b][l,6]naphthyridine and 10-amino-l-benzyl 1 ,2,3,4-tetrahydro-2-methylbenzo[b][ l,6]naphthyridine are produced.

EXAMPLE XLV A mixture of 2-amino-4-chlorobenzonitrile (2.5 g.) and 1- benzyl -4-piperidone (2.5 g.) in trifluoroacetic acid g.) is gradually heated to reflux, and maintained at this temperature for 1 hour. The reaction mixture is then poured into cold water (500 ml. The resultant solution is filtered, and the filtrate basified with 1N solution hydroxide. The crude product is collected by filtration and washed with water to yield the desired lO-amino-2-benzyl-7-chloro-1,2,3,4- tetrahydrobenzo[ b 1,6]naphthyridine.

Dry hydrogen chloride is passed into an ether solution of the above prepared l-amino-2-benzyl-7-chloro- 1 ,2,3,4- tetrahydrobenzo[b][ 1,6]naphthyridine. Thereafter, the resulting dihydrochloride salt is recrystallized from absolute ethanol to yield colorless crystals thereof.

EXAMPLE XLVl A mixture of 2-amino-3-chloro-benzonitrile (1.0 g.) and lphenethyl-4-piperidone (1.0 g.) in acetic acid (50.0 g.) is heated to reflux for 16 hours. The reaction mixture is then poured into cold water (200 ml.). The resultant solution is filtered, and the filtrate basified with 1.5N potassium hydroxide. The crude product is collected by filtration and washed with water to yield the desired l0-amino-6-chloro-1,2,3-,4- tetrahydro-2-phenethylbenzo[b][ 1,6]naphthyridine.

Similarly, -amino-2-(p-chlorophenyl)-1,2,3,4-tetrahydro- 8-iodobenzo[b][ 1,6]naphthyridine and 10-amino-2-( pbromophenyl)-7-butyl-1,2,3,4-tetrahydro[b][ 1,6] naphthyridine are synthesized.

EXAMPLE XLVll A mixture of 2-amino-4-methylbenzonitrile (10.0 g.) and lbenzoyl-4-piperidone (10.0 g.) in benzenesulfonic acid (100 g.) is gradually heated to 100 C., and maintained at this temperature for 1 hour. The reaction mixture is then poured into cold water (1,500 ml.). The resultant solution is filtered, and the filtrate basified with 1.5N soidum hydroxide. The crude product is collected by filtration and washed with water to yield the desired 10-amino-2-benzoyl-l,2,3,4-tetrahydro-7- methylbenzo[b][1,6]naphthyridine.

Dry hydrogen chloride gas is passed into a tetrahydrofuran solution of the above prepared l0-amino-2-benzoyl-l,2,3,4- tetrahydro-7-methylbenzo[b][ 1,6]naphthyridine. The resulting salt is recrystallized from ethanol to yield a crystalline l0- umino-2-benzoyl-l,2,3,4-tetrahydro-7-methylbenzo[b][1,6] naphthyridine dihydrochloride.

EXAMPLE XLVlll Additional bcnzo[b|[ 1,6]naphthyridines having the formu- In:

are prepared according to the procedures of the above examples where R, R,, R and R are defined as follows:

A mixture of Z-aminobenzonitrile (2.0 g.) and 2,2,6,6- tetramethyl-4-piperidone (2.0 g.) in polyphosphoric acid g.) is gradually heated to C., and maintained at this temperature for 1% hours. The reaction mixture is then poured into cold water (400 ml.). The resultant solution is filtered, and the filtrate basified with 0.5N sodium hydroxide. The crude product is collected by filtration and washed with water to yield the desired 10-amino-2-butyl-l,2,3,4-tetrahydro- 1,1,3,3-tetramethylbenzo [b][1,6]naphthyridine.

Similarly, the lO-amino-2-ethyll ,2,3,4-tetrahydrol l ,3,3- tetramethylben2o[b]e[1,6]naphthyridine and the IO-aminol,2,3,4-tetrahydro-1,l,3,3-tetramethylbenzo[b] l ,6]naphthyridine are prepared.

EXAMPLE L A mixture of 2-aminobenzonitrile (5.0 g.) and l-ethylsulfonyl-4-piperidone (5.0 g.) in ethylsulfonic acid (150 g.) is gradually heated to 150 C., and maintained at this temperature for 2 hours. The reaction mixture is then poured into cold water (1,200 ml.). The resultant solution is filtered, and the filtrate basified with 45 percent potassim hydroxide. The crude product is collected by filtration and washed with water to yield the desired l0-amino-2-ethysulfonyl-l,2,3,4- tetrahydrobenzo[b][ l ,6] naphthyridine.

The dihydrochloride of the above prepared 10-amino-2- ethylsulfonyll ,2,3,4-tetrahydrobenzo[b][ 1,6]naphthyridine is prepared in accord with the procedure of Example XLlV.

EXAMPLE Ll The following benzo[b][1,6]naphthyridines having the formulae:

are prepared according to the procedure of the prior examples, employing the appropriate 2-aminobenzonitrile and 4- piperidone compounds as starting materials:

10-amino-8-chloro-l ,2,3 ,4-tetrahydro- 1 (p-methoxyphenyl)-2-methylbenzo[b][ 1,6]naphthyridine;

l0-amino-8-chloro-1,2,3,4-tetrahydro-3-(p-methoxyphenyl)-2-methylbenzo[b][ 1,6]naphthyridine;

10-amino l ,2,3,4-tetrahydro-2-methoxyethyl-3-phenethylbenzo[b][ 1,6]naphthyridine;

IO-aminol ,2,3 ,4-tetrahydro-2-methoxyethyll -phenethylbenzo[b][ 1,6]naphthyridine;

10-amino-7-ethyl- 1 ,2,3,4-tetrahydro-2-propionylbenzo[ b 1,6 ]naphthyn'dine;

10amino-3-butyl-2-diethylcarbamoyl-1,2,3,4- tetrahydrobenzo[ b][ 1,6]naphthyridine;

IO-amino-1-butyl-2-diethylcarbamoyl-1,2,3 ,4- tetrahydrobenzo[b][ 1 ,6]naphthyridine;

10-amino-3-(p-bromophenyl 1 ,2,3 ,4-tetrahydrobenzo[ b] 1,6]naphthyn'dine;

10-amino-1-(p-bromophenyl)-1 ,2,3 ,4-tetrahydrobenzo[ b] 1,6]naphthyridine; and

10-amino-1,2,3,4-tetrahydro-2-(p-tolyl)benzolb][ 1,6]naph thyridine.

EXAMPLE LII A mixture of 2-aminobenzonitrile -(10.0 g.) and 2,6- diemthyl-4-piperidone (10.0 g.) in methylsulfonic acid (120 g.) is gradually heated to 145 C., and maintained at this temperature for 2 hours. The reaction mixture is then poured in cold water (2,000 ml.). The resultant solution is filtered, and the filtrate basified with 1N sodium hydroxide. The crude product is collected by filtration and washed with water to yield the desired IO-amino-l,2,3,4-tetrahydro-1,3-dimethylbenzo[b][ 1,6]naphthyridine.

Employing the above procedure the following compounds are also prepared:

-amino-3-(p-chlorophenyl )-1 ,2,3 ,4-tetrahydro-2-propylbenzo[b][ 1,6]naphthyridine;

10-amino-1-(p-chlorophenyl)- l ,2,3,4-tetrahydro2-propylbenzo[b] 1,6]naphthyridine;

10-amino-1,2,3,4 tetrahydro-2-methyl-3-(p-propyl-phenyl)benzo[b][ 1,6]naphthyridine;

10-amino-1,2,3 ,4-tetrahydro-2-methyl- 1 p-propyl-phenyl)benzo[b][ 1,6]naphthyridine; and

10-amino-1 ,2,3 ,4-tetrahydro-8-iodo-2-( m-iodophenyl) benzo b] bh 1 ,6]naphthyridine.

EXAMPLE LIll A solution of IO-amino-l,2,3,4-tetrahydro-2-methylbenzo[b][1,6]naphthyridine dihydrochloride, as prepared in Example XLIV, (0.0156 m.) in glacial acetic acid (100 ml.) containing platinum oxide (0.3 g) is hydrogenated at room temperature, and an initial hydrogen pressure of 46.5 psi for a period of 24 hours. The excess acetic acid is distilled in vacuo, the residue dissolved in water, and then basified whereupon the crude product separates. Recrystallization from cyclohexane-hexane affords 10-amino-1,2,3,4,4a,5,10,10a-octahydro- 2-methylbenzo[b][ 1,6]naphthyridine.

When the above procedure is repeated for the IO-amino- 1,2,3 ,4,4a,5 l0,10-octahydrobenzo[b][ 1,6]naphthyridines of Examples XLV-Lll, the corresponding IO-amino- 1,2,3,4,4a,5,10,10-octahydrobenzo[b][ 1,6]naphthyridines are obtained.

EXAMPLE LIV 1-Methyl-4-piperidone (66.0 g., 0.58 m.) is slowly added to a slurry of 4-chloroanthrani1ic acid (100.0 g., 0.58 m.) in phosphorous oxychloride (500 ml.) and the resulting mixture refluxed for 2 hours. The solvent is evaporated and the residue taken up in methylene chloride (2 liters). This is slowly added to a stirred ammonium hydroxideice solution (10 liters). The methylene chloride solution is washed with water, dried over anhydrous sodium sulfate and evaporated giving 139.0 g. of a green solid. This solid is extracted with 1.5 l. of hexane, treated with charcoal, concentrated and crystallized giving 79.0 g. (49 percent) of crude product. Recrystallization from hexane gives 7,10-dichloro-1,2,3,4-tetrahydro-2-methylbenzo[b][ 1,6]naphthyridine as a yellow crystalline solid, m.p. 1145 C. (uncorr.).

Anal. Calcd for C H Cl- N C, 58.46; H, 4.53; N, 10.49.

Found: C, 58.63; H, 4.28; N, 10.23.

The above prepared 7,IO-dichloro-l,2,3,4-tetrahydro-2- methylbenzo[b]1,6]naphthyridine (5.0 g, 0.018 m), and 3.36 g. (0.036 m.) of phenol are heated under nitrogen at 100 C. for minutes until a clear melt is obtained. Aniline (3.3 ml., 0.036 m.) is then added dropwise with stirring and the mixture is heated at 135140 C. for 5 hours. The reaction product is dissolved in methylene chloride and extracted with a percent potassium hydroxide solution. After being dried over anhydrous sodium sulfate, the methylene chloride solution is evaporated giving the free base. This product is triturated with ethyl acetate and recrystallized twice from acetonitrile giving 4.0 g. (69 percent) of l0'anilino-7-chloro-l,2,3,4-tetrahydro- 2-methylbenzo[b][1,6]naphthyridine as a crystalline solid, m.p. 197-8 C. (red melt) (uncorr.).

Anal. Calcd for c,,H,,c1N,= C, 70.47; H, 5.60; N, 12.98.

Found: C, 70.40; H, 5.40; N, 12.72.

In a similar manner, the following compounds are prepared:

7,10-Dichloro-1 ,2,3,4-tetrahydro-2-methylbenzo[ b] [1,6]naphthyridine (5.0 g., 0.018 m.) and phenol (3.38 g., 0.036 m.) are reacted to form the free base which is recrystallized three times from hexane to yield 7-chloro-1,2,3,4- tetrahydro-Z-methyl-10-phenoxybenzo[b][ 1 ,6 lnaphthyridine as a crystalline solid, m.p. 138-9 C. (uncorr.

Anal. Calcd for C,,,H ClN 0: C, 70.25; H, 5.27; N, 8.64.

Found: C, 70.50; H, 4.91; N. 8.87.

7, 10-Dichloro-1 ,2,3,4-tetrahydro-2-methylbenzo[ b] [1,6]naphthyridine (8.0 g., 0.03 m.), 5.65 g. (0.06 m.) of phenol and 7.0 g. (0.07 m.) of N-methylpiperazine are reacted to form the free base which is triturated with pentane and recrystallized from hexane giving 7-chloro-1,2,3,4-tetrahydro- 2-methyll 0-( 4-methyl- 1 -piperazinyl )benzo[ b] 1,6]naphthyridine as a crystalline solid, m.p. 1 14-5 C. (uncorn).

Anal. Calcd for C,,,H, ClN,: C, 65.33; H, 7.02; N, 16.94.

Found: C, 65.74; H, 6.97; N, 16.79.

7, l O-Dichlorol ,2,3,4-tetrahydro-2-methy1benzo[ b] [1,6]naphthyridine 10.0 g., 0.0375 m.), 7.05 g. (0.075 m.) of phenol and 8.1 g. (0.075 m.) of o-phenylenediamine are reacted to form the free base which is triturated with carbon tetrachloride and recrystallized twice from methanol giving 10-(o-aminoanilino)-7-chloro-1,2,3,4-tetrahydro-2-methylbenzo [b][1,6]naphthyridine as a crystalline solid, m.p. l89-192 C. (uncorr.

Anal. Calcd for C H ClM: C, 67.35; H, 5.65; N, 16.54.

Found: C, 67.23; H, 5.79; N, 16.39.

When the above products are hydrogenated by the process of Example LIll, the following compounds are obtained:

10-anilino-7-chloro-1,2,3,4,4a,5,10,10a-octahydro-2- methylbenzo[ b][ 1,6]naphthyridine;

7-chloro-l,2,3,4,4a,5,l0,10a-octahydro-2-methyl-10- phenoxybenzo[b][ 1,6]naphthyridine;

7chloro-1,2,3 ,4,4a,5,l0,l0a-octahydro-2-methyl-10-(4- methyl-l-piperazinyl)benzo[b][ 1,6]naphthyridine; and

10-(oaminoanilino)-7-chloro-1,2,3,4,4a,5 ,10,10-octahydro-2-methylbenzo[b] 1 ,6]naphthyridine;

EXAMPLE LV ychlon'de (800 ml.) are allowed to react in a manner similar to Example LIV. The crude product is extracted several times with hot hexane. The combined extracts are concentrated and the product allowed to crystallize giving 140 g. (45 percent) of solid. Recrystallization of the crude product from hexane gives 8, 10-dichloro- 1 ,2,3 ,4-tetrahydro-2-methylbenzo[ b] 1,6]naphthyridine as a crystalline solid, m.p. 88-9 C. (uncorr.).

Anal. Calcd. for C H CI N C, 58.46; N, 4.53; N, 10.49.

Found: C, 58.51; H, 4.31; N, 10.38.

The above-prepared 8,10-dichloro-1,2,3,4-tetrahydro-2- methylbenzo[b]1,6]naphthyridine (5.0 g., 0.018 m.) and phenol (3.38 g., 0.036 m.) are reacted as described in the second paragraph of Example LlV to obtain the free base which is recrystallized three times from hexane to afford 8- chloro-l ,2,3,4-tetrahydro-2-methyll 0-phenoxybenzo[ b] [1,6]naphthyridine as a crystalline solid, m.p. 182-4 C. (uncorn).

Anal. Calcd. for C H,-,ClN O: C, 70.25; H, 5.27; N, 8.64; CI, 10.9].

Found: C, 70.39; H, 5.07; N, 8.77; Cl, 10.89.

In the same manner, the following compounds are prepared:

8, 1 O-Dichlorol ,2,3 ,4-tetrahydro-2-methylbenzo[b] [1,6]naphthyridine (15.0 g., 0.0562 m.), 10.6 g. (0.115 m.) of phenol and 10.3 ml. (0.115 m.) of aniline are reacted. Thereafter the reaction mixture is slurried with a mixture of 10 percent aqueous potassium hydroxide and diethyl ether. The insoluble product is filtered and recrystallized from acetonitrile giving l0-anilino-8-chloro-1,2,3,4-tetrahydro-2- methylbenzo[b][ 1,6]naphthyridine as a crystalline solid 13.0 g., 72 percent, m.p. l87- C. (red melt) (uncorr.).

Anal. Calcd for c H ClN C, 70.47; H, 5.60; N, 12.98.

Found: C, 70.51; H, 5.40; N, 13.14.

8, l-Dichloro-1,2,3 ,4-tetrahydro-2-methylbenzo[ b] [1,6]naphthyridine (8.0 g., 0.03 m.), 5.65 g. (0.06 m.) of phenol and 6.1 g. (0.06 m.) of dimethylaminopropylamine are reacted and the resulting free base is then recrystallized from cyclohexane followed by trituration with hexane to afford 8- chloro-1,2,3 ,4-tetrahydro-2-methyll 0-[ 3-dimethylamino propyl)amino]benzoeqb][1,6]naphthyridine as a crystalline solid, (5.0 g., 50 percent) m.p. l07-8 C. (uncorr.).

Anal. Calcd for C H ClN C, 64.94; H, 7.57; N, 16.83.

Found: C, 65.23; H, 7.86; N, 16.84.

EXAMPLE LVl 5-Methoxyanthranilic acid (10.0 g., 0.0598 m.), l-methyl- 4-piperidone (13.5 g., 0.112 m.) and phosphorous oxychloride 150 ml.) are allowed to react in a manner similar to Example LIV. The crude product is extracted several times with hot cyclohexane. The combined extracts are concentrated and the product allowed to crystalline. Recrystallization of the crude product from the same solvent gives l0-chlorol,2,3,4-tetrahydro-8-methoxy-2-methylbenzo[b][ 1,6] naphthyridine (4.0 g., 25 percent), m.p. 1267 C. (uncorr.)

Anal. Calcd. for C,.,H, ClN O: C, 64.00; H, 5.76; N, 10.66.

Found: C, 64.07; H, 5.46; N, 10.57.

When the above prepared naphthyridine is reacted with dimethylaminoethylamine by the procedure of the second paragraph of Example LIV, there is obtained 1,2,3,4- tetrahydro-8-methoxy-2-methyl-10-[(2- dimethylaminoethyl)amino]benzo[b][1,6]naphthyridine.

Similarly, the following products are obtained:

1 ,2,3,4-tetrahydro-8-methoxy-2-methyl-10-[(4- dipropylaminobutyl)amino]benzo[b][ 1,6]naphthyridine;

l0-( 4-ethyl-l-piperazinyl)- l ,2,3,4-tetrahydro-8-methoxy-2- methylbenzo[b]1,6]naphthyridine;

10-[(3-diethylaminopropyl )amino]- 1 ,2,3,4-tetrahydro-8- methoxy-2-methylbenzo[b][ l ,61naphthyridine; and

10-( 4-butyll -piperazinyl l ,2,3,4-tetrahydro-8-methoxy- 2-methylbenzo[b][1,6]naphthyridine.

EXAMPLE LVll l0-Chloro-1,2,3,4-tetrahydro-2methyl-8-nitro-benzo[b ][l,6]ahnaphthyridine (5.0 g., 0.018 m.) and phenol (3.38 g., 0.036 m.) is heated under nitrogen at 100 C. for 15 minutes until a clear melt is obtained. Morpholine (3.50 ml., 0.040 m.) is then added dropwise with stirring and the mixture is heated at l35-l40 C. for 5 hours. The reaction product is dissolved in methylene chloride and extracted with a 20 percent potassium hydroxide solution. After being dried over anhydrous sodium sulfate, the methylene chloride solution is evaporated giving the free base. This product is triturated with ethyl acetate and recrystallized from benzene giving 1,2,3,4-tetrahydro-2- methyl- 1 0 -morpholino-8-nitrobenzo[b][1,6]naphthyridine as a crystalline solid, mp. 216-7 C. (uncorr.

Anal. Calcd for C H Nfl z C, 62.17; H, 6.14; N,17.06.

Found: C, 61.99; H, 5.92; N, 16.98.

EXAMPLE LVlll Anal. Calcd for C H CIN S: C, 66.94; H, 5.03; N, 8.22. Found: C, 67.21; H, 4.73; N, 8.11.

EXAMPLE LlX A solution of 5.0 g. (0.0188 m.) of 8,l0-dichloro-1,2,3,4- tetrahydro-2-methylbenzo[ b][ 1,6]naphthyridine, 3.3 g. (0.0244 m.) of 3-aminopropanethiol hydrochloride, 15 ml. of 18.5 percent aqueous potassium hydroxide (0.05 m.) and 30 ml. of absolute ethanol is refluxed for 1% hours. After evaporation of the solution the residue is dissolved in methylene chloride and extracted with water. Evaporation of the methylene chloride solution gives the free base. Recrystallization of the product from hexane affords 10-(3- aminopropylthio )-8-chlorol ,2,3 ,4-tetrahydro-2-methylbenzo[b][1,6]naphthyridine as a crystalline solid (3.2 g, 53 percent), m.p. 8789 C. (uncorr.).

Anal. Calcd for C H CIN S: C, 59.70; H, 6.26; N, 13.05; S, 9.96.

Found: C, 60.27; H, 6.40; N, 13.02; S, 9.95.

EXAMPLE LX A solution of 4.0 g (0.015 m) of 7,l0-dichloro-l,2,3,4- tetrahydro-2-methylbenzo[b][1,6]naphthyridine, 3.2 ml. (0.03 m.) of phenylhydrazine, 2.5 ml. of concentrated hydrochloric acid and 150 ml. of absolute ethanol is refluxed for 6 hours. After cooling the solution, a yellow solid is filtered which is then dissolved in methanol. To this solution is slowly added an aqueous sodium carbonate solution thereby effecting the precipitation of the free base. Two recrystallization of the product from benzene gives l-( 7-chloro-1,2,3,4- tetrahydro-2-methylbenzo[ b 1,6 ]naphthyrin- 1 O-yl )-2-phenylhydrazine as a crystalline solid, mp. 1768 C. (decomp.) (uncorr.).

Anal. Calcd. for C, H, ClN C, 67.35; H, 5.65; N, 16.54.

Found: C, 67.76; H, 5.43; N, 16.12.

EXAMPLE LXl A solution of 5.0 g. (0.0187 m.) of 8,10-dichloro-l,2,3,4- tetrahydro-2-methylbenzo[b][ 1,6]naphthyridine, 3.5 g. (0.074 m.) of percent hydrazine and 50 ml. of n-propyl alcohol is refluxed for 4 hours. The solution is evaporated and the residue treated simultaneously with methylene chloride and a sodium carbonate solution leaving an insoluble solid (2.0 g., 41 percent). Recrystallization of the product from benzene affords (8-chloro-l,2,3,4-tetrahydro-2-methylbenzo[b][ l,6]naphthyridin-l0-yl)hydrazine as a crystalline solid, mp. l72-3 C. (uncorr.

Anal. Calcd. for C,;,H, =,C1N.,: C, 59.44; H, 5.75; N, 21.33.

Found: C, 59.20; H, 5.66; N, 21.31.

EXAMPLE LXll A solution of 8-chloro-l,2,3,4-tetrahydro-2-methyl-l0- phenoxybenzo[b][1,6]naphthyridine (0.0312 111.) in glacial acetic acid (200 ml.) containing platinum oxide (0.6 g.) is hydrogenated at room temperature, and an initial hydrogen pressure of 46.5 psi for a period of 24 hours. The excess acetic acid is distilled in vacuo, the residue dissolved in water, and then basified whereupon the crude product separates. Recrystallization from cyclohexane-hexane affords 8-chlorol ,2,3,4,4a,5,10,102-methyl-l0-phenoxybenzo[ b][ 1,6]naphthyridine.

When the above procedure is repeated using the products of Examples LV-LXl as reactants, the following corresponding hydrogenated compounds are obtained:

l0-anilino-8-chloro-1,2,3,4,4a,5,10,10a-oetahydro-2- methylbenzo[b][ 1 ,6]naphthyridine;

8-chloro-1 ,2,3 ,4,4a,5, l 0, l Oa-octahydro-Z-methyll 0-[ (3- dimethylaminopropyl)amino]benzo[b][ 1,6]napthyridine;

l,2,3,4,4a,5,10,10a-octahydro-8-methoxy-2-methyl-l0- [(2-dimethylaminoethyl)amino]benzo[b][1,6]naphthyridine;

l,2,3,4,4a,5,10,l0a-octahydro-8-methoxy-2-methyl-10- [(4-dipropylaminobutyl)amino]benzo[b][ 1,6]naphthyridine;

l-(4-ethyl-l-piperazinyl)-1,2,3,4,4a,5 l0, lOa-octahydro- 8-methoxy2-methylbenzo[b][ 1,6]naphthyridine;

l0-[(3-diethylaminopropyl)aminol-1,2,3,4,4a,5,lO,l0a-octahydro-8-methoxy-2-methylbenzo[b][ 1,6]naphthyridine;

lO-(4-butyll -piperazinyl)- l ,2,3,4,4a,5 10, l Oa-octahydro- 8-methoxy-2-methylbenzo[b][ 1,6]naphthyridine;

S-aminol ,2,3 ,4,4a,5 l0, l0a-octahydro-2-methyll0- morpholinobenzo[b][ l ,6]naphthyridine;

7-chlorol ,2,3 ,4,4a,5 l 0, l Oa-octahydro-Z-methyll 0 phenthiobenzo[b][ 1,6]naphthyridine;

l0-( 3-aninopropylthio)-8-chlorol ,2,3,4,4a,5, l0, lOa-octahydro-2-methylbenzo[b][ 1,6]naphthyridine;

1-( 7-chlorol ,2,3 ,4,4a,5,10,]0a-octahydro-Z-methylbenzo [b][ 1,6]naphthyridinl O-yl. )-2-phenylhydrazine; and

(8-chlorol ,2,3 ,4,4a,5, l 0, l Oa-octahydro-Z-methyl-benzo[ b 1,6]naphthyridinl O-yl )hydraxine.

EXAMPLE LXllI An ethanolic solution of 2-benzyl-8-chloro-l ,2,3,4- tetrahydrol 0-phenylbenzo[ b l ,6]naphthyridine hydrochloride (10.0 g., 0.0238 m.) is hydrogenated at three atmospheres of H pressure in the presence of a palladium catalyst, for 30 hours then at 60 C. for 20 hours. A total of 0.05 1 moles of hydrogen is consumed during this period. After separation of the catalyst by filtration, the solvent is distilled in vacuo and the solid residue recrystallized from absolute ethanol to yield colorless crystals of l,2,3,4-tetrahydro-l0- phenylbenzo[b][1,6]naphthyridine dihydrochloride, m.p. 276.5277 C. (uncorr.).

Anal. Calcd for C H Cl N C, 64.85; H, 5.45; Cl, 21.29; N, 8.41.

Found: C, 64.58; H, 5.35; Cl, 21.0; N, 8.18.

EXAMPLE LXlV The citrate salt of 8-chloro-l,2,3,4-tetrahydro-2-methyl-l0- phenylbenzo[b][1,6]naphthyridine is prepared by admixing an ethanolic solution of the compound with an aqueous solution containing two molar equivalents of citric acid and, thereafter, evaporating the co-solvents under vacuum.

Other acid addition salts of the l,2,3,4- tetrahydrobenzonaphthyridine and l,2,3,4,4a,5, 10,10a-octahydrobenzonaphthyridine compounds described in the above examples are prepared by similar procedures employing hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, phosphoric acid, tartaric acid, acetic acid, succinic acid, maleic acid and gluconcic acid.

What is claimed is:

1. A compound selected from the group consisting of those having the formulas:

wherein R and R, are the same and are selected from the group consisting of hydrogen, halogen, and lower alkoxy, R is selected from the group consisting of hydrazine, amino, amino-aniline, anilino, di(lower)alkylamino (lower)alkylamino, amino-(lower)alkylthio, phenyl, phenyl-hydrazino, halophenyl, lower alkylphenyl, lower alkoxyphenyl, lower alkylthiophenyl, phenoxy, phenthio, and Z-thienyl; and R is selected from the group consisting of hydrogen, lower alkyl, phen(lower)alkyl, benzoyl, halo(lower)alkanoyl, dihalo(lower) alkanoyl, di(lower)alkylamino-(lower) alkanoyl, di(lower)alkylamino-(lower)alkyl, dihydroxy(lower)alkyl and 5,5-dimethyl-3-oxo'lcyclohexen-l-yl; R and R are both selected from the group consisting of hydrogen and dimethyl, and the pharmacologically acceptable acid addition salts thereof, wherein the lower alkyl group or the lower alkyl-moiety in R, R, R or R is from one to six carbon atoms.

2. The compound as defined in claim 1 formula (l) which is: 8-chlorol ,2,3,42-methyll 0-phenyl-benzo[ b] 1,6]naphthyridine.

3. The compound as defined in claim 1 formula (I) which is: 2-benzyl-8-chlorol ,2,3,4-tetrahydrol0-phenyl-benzo[ b] 1,6]naphthyn'dine.

4. The compound as defined in claim 1 formula (ll) which is: 2-benzyl-8-chlorol ,2,3,4,4a,5 l 0, l Oa-octahydrol O-phenylbenzo[b][ 1,6]naphthyridine.

5. The compound as defined in claim 1 formula l) which is: 8-chloro-lO-(o-chlorophenyl)-1,2,3 ,4-tetrahydro-2-methylbenzo[b][ 1,6]naphthyridine.

6. The compound as defined in claim 1 formula (I) which is: 8-chloro- 1 ,2,3,4] l ,3,3-tetramethyll O-phenylbenzo[b][ l,6]naphthyridine.

7. The compound as defined in claim 1 formula (I) which is: l,2,3,4tetrahydro-0-phenylbenzo[b][ 1,6]naphthyridine.

8. The compound as defined in claim 1 formula (I) which is: 8-chloro-l0-(o-chlorophenyl)-1,2,3 ,4-tetrahydro-l l ,3 ,3- tetramethylbenzo[ b]e[ l ,6 ]naphthyridine.

9. The compound as defined in claim 1 formula (I) which is: 2-benzoyl-8-chlorol ,2,3 ,4-tetrahydrol 0-phenylbenzo[b] 1,6]naphthyridine.

10. The compound as defined in claim 1 formula (I) which is: 8-chloro-l ,2,3 ,4-tetrahydrol 0 phenylbenzo[b][ l ,6 naphthyridine.

11. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-chloroacetyll ,2,3 ,4-tetrahydrol 0-phenylbenzo[b][ l ,6]naphthyridine.

12. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-( 2,3-dihydroxypropyl l ,2,3,4-tetrahydrol 0- phenylbenzo[b][ 1,6]naphthyridine.

13. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-( 2-diethylaminoacetyl l ,2,3,4-tetrahydrol0- phenylbenzo[b][ 1,6]naphthyridine.

14. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-dichloroacetyll ,2,3,4-tetrahydrol O-phenylbenzo[b][ l,6]naphthyn'dine.

15. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-( 3-dimethylaminopropyl)-l ,2,3,4-tetrahydrol0-phenylbenzo[ b][ l ,6]naphthyridine.

16. The compound as defined in claim 1 formula (I) which is: 2-benzyl-6,8-dichlorol ,2,3,4-tetrahydrol O-phenylbenzo[b][ l,6]naphthyridine.

17. The compound as defined in claim 1 formula (I) which is: 2-benzyl-7,8-dichloro l ,2,3 ,4-tetrahydrol 0-( p-methoxyphenyl )benzo[b][ 1 ,6]naphthyridine.

18. The compound as defined in claim 1 formula (I) which is: 2-benzyl-6-chloro-l ,2,3 ,4-tetrahydrol O-phenylbenzo b] 1,6]naphthyridine.

19. The compound as defined in claim 1 formula (I) which is: 2-benzyl-8-chloro l 0-( p-chlorophenyl l ,2, 3 ,4- tetrahydrobenzo[b][ l ,6]naphthyridine.

20. The compound as defined in claim 1 formula (I) which is: 2-benzyl-8-chlorol ,2,3 ,4-tetrahydrol O-(p-methoxyphenyl )benzo[b] l ,6]naphthyridine.

21. The compound as defined in claim 1 formula (I) which is; l ,2,3 ,4-tetrahydrol l ,3,3-tetramethyll 0-( ptolyl)benzo[b][l ,6] naphthyridine.

22. The compound as defined in claim 1 formula (I) which is; 6-chlorol ,2,3 ,4-tetrahydro-l 1 ,3 ,3tetramethyl-10-pheny1benzo[b][ 1,6]naphthyridine.

23. The compound as defined in claim 1 formula (I) which is: 7,8-dimethoxy-l ,2,3 ,4-tetrahydrol l ,3,3-tetramethyll0- (p-methoxyphenyl)benzo[b][ l ,6]naphthyridine.

24. The compound as defined in claim 1 formula (I) which is: 7-chlorol ,2,3,4-tetrahydro-2-methyll 0-( Z-thienyl benzo[b][ 1,6 ]naphthyridine.

25. The compound as defined in claim 1 formula (I) which is: 7-chloro-l ,2,3,4-tetrahydrol l ,3 ,B-tetramethyll 0-( pmethylthiophenyl )benzo[bfq l ,6]naphthyridine.

26. The compound as defined in claim 1 formula (I) which is: 2-benzyl-7-chlorol ,2,3 ,4-tetrahydrol O-phenylbenzo[ b] l,6 ]naphthyridine.

27. The compound as defined in claim 1 formula (I) which is: 8-chlorol ,2,3,4-tetrahydrol l .2,3,3-pentamethyll O- phenylbenzo[b][1,6]naphthyridine.

28. The compound as defined in claim 1 formula (I) which is: l,2,3,4-tetrahydro-2-phenethyl lO-phenylbenzo[b][ 1,6]naphthyridine.

29. The compound as defined in claim 1 formula (I) which is: 2-benzyll ,2,3 ,4-tetrahydrol -phenylbenzo[ b 1,6]naphthyridine.

30. The compound as defined in claim 1 formula (I) which is: 3-( 8-chlorol ,2,3,4-tetrahydrol O-phenylbenzo[b][ L6] naphthyridin-Z-yl ,5-dimethyl-2-cyclohexen- 1 -one.

31. The compound as defined in claim 1 formula (I) which is: lO-anilino-7-chloro-l,2,3,4-tetrahydro-2-methylbenzo[b] 1,6]naphthyridine.

32. The compound as defined in claim 1 formula (I) which is: 7-chloro-l,2,3,4-tetrahydro-2-methyl-10-phenoxybenzo[b] 1,6]naphthridine.

33. The compound as defined in claim 1 formula (I) which is: o-aminoanilino )-7-chlorol ,2,3,4-tetrahydro-2- methylbenzo[b][ 1,6]naphthyridine.

34. The compound as defined in claim 1 formula (I) which is: 8-chlorol ,2,3,4-tetrahydro-2-methyll O-phenoxybenzo[b] 1,6]naphthyridine.

35. The compound as defined in claim 1 formula (1) which is: lO-anilino-S-chlorol ,2,3 ,4-tetrahydro-2-methylbenzo[b] [l,6]naphthyridine.

36. The compound as defined in claim 1 formula (I) which is: 8-chloro-l ,2,3 ,4-tetrahydro-2-methyll 0-[ 3- dimethylaminopropyl )amino]benzo[b][ 1,6]napthyridine.

37. The compound as defined in claim 1 formula (1) which is: 7-chlorol ,2,3 ,4-tetrahydro-2-methyll 0- phenthiobenzo[b][ 1,6]naphthyridine.

38 The compound as defined in claim 1 formula (I) which is: l0-(3-aminopropylthio)-8-chloro-1 ,2,3,4-tetrahydro-2- methylbenzo[b][ l ,6]naphthyridine.

39. The compound as defined in claim 1 formula (1) which is: l-( 7-chlorol ,2,3,4-tetrahydro-2-methylbenzo[b][ 1,6] naphthyridinlO-yl )-2phenylhydrazine.

40. The compound as defined in claim 1 formula (I) which is: (8-chlorol ,2,3,4-tetrahydro-Z-methylbenzo[b][ 1,6]- naphthyridinl O-yl )hydrazine.

41. A process for the production of a compound having the formula:

N Ii;

,- lin wherein R and R are the same and are selected from the group consisting of hydrogen, halogen, and lower alkoxy; R is selected from the group consisting of hydrogen, lower alkyl, phen(lower)alkyl, benzoyl, halo( lower)alkanoyl. dihalo(lower) ulkanoyl, di(lower)alkylamino(lower) al kanoyl, di-(lower)alkylamino(lowcr)alkyl, dihydroxy(lower)alkyl and 5.5-dimethyl-3-oxo-l'cyclohexcn-l-yl; R and R are both selected from the group consisting of hydrogen and dimcthyl, wherein the lower alkyl group or the lower alkyl moiety in R, R or R is from one to six carbon atoms, which comprises contacting a Z-aminobenzoitrile having the formula:

wherein R and R are defined as above, with a 4-piperidone having the formula:

l N-R:

wherein R R and R are defined as above, in the presence of a strong acid selected from the group consisting of polyphosphoric, trifluoroacetic, acetic, benzensulfonic, toluenesulfonic, methyl sulfonic, and ethylsulfonic, at a temperature that is in the range from about to about 200 C. for a period of from about one-half to about 2 hours.

42. A process as described in claim 41 wherein the strong acid is polyphosphoric acid.

43. A process as described in claim 41 wherein the strong acid is polyphosphoric acid and the reaction is conducted at about l50 C. for about l hour. 

2. The compound as defined in claim 1 formula (I) which is: 8-chloro-1,2,3,4-tetrahydro-2-methyl-10-phenyl-benzo(b)(1, 6)naphthyridine.
 3. The compound as defined in claim 1 formula (I) which is: 2-benzyl-8-chloro-1,2,3,4-tetrahydro-10-phenyl-benzo(b)(1, 6)naphthyridine.
 4. The compound as defined in claim 1 formula (II) which is: 2-benzyl-8-chloro-1,2,3,4,4a,5,10,10a-octahydro-10 -phenylbenzo(b)(1,6)naphthyridine.
 5. The compound as defined in claim 1 formula (I) which is: 8-chloro-10-(o-chlorophenyl)-1,2,3,4-tetrahydro-2-methylbenzo(b)(1, 6)naphthyridine.
 6. The compound as defined in claim 1 formula (I) which is: 8-chloro-1,2,3,4-tetrahydro-1,1,3,3-tetramethyl-10 -phenylbenzo(b)(1,6)naphthyridine.
 7. The compound as defined in claim 1 formula (I) which is: 1,2, 3,4-tetrahydro-10-phenylbenzo(b)(1,6)naphthyridine.
 8. The compound as defined in claim 1 formula (I) which is: 8-chloro-10-(o-chlorophenyl)-1,2,3,4-tetrahydro-1,1,3,3 -tetramethylbenzo(b)(1,6)naphthyridine.
 9. The compound as defined in claim 1 formula (I) which is: 2-benzoyl-8-chloro-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1, 6)naphthyridine.
 10. The compound as defined in claim 1 formula (I) which is: 8-chloro-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1,6)-naphthyridine.
 11. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-chloroacetyl-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1, 6)naphthyridine.
 12. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-(2,3-dihydroxypropyl)1,2,3,4-tetrahydro-10 -phenylbenzo(b)(1,6)naphthyridine.
 13. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-(2-diethylaminoacetyl)-1,2,3,4-tetrahydro-10 -phenylbenzo(b)(1,6)naphthyridine.
 14. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-dichloroacetyl-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1, 6)naphthyridine.
 15. The compound as defined in claim 1 formula (I) which is: 8-chloro-2-(3-dimethylaminopropyl)-1,2,3,4-tetrahydro-10 -phenylbenzo(b)(1,6)naphthyridine.
 16. The compound as defined in claim 1 formula (I) which is: 2-benzyl-6,8-dichloro-1,2,3,4-tetrahydro-10-phenylbenzo( b)(1, 6)naphthyridine.
 17. The compound as defined in claim 1 formula (I) which is: 2-benzyl-7,8-dichloro-1,2,3,4-tetrahydro-10-(p -methoxyphenyl)benzo(b)(1,6)naphthyridine.
 18. The compound as defined in claim 1 formula (I) which is: 2-benzyl-6-chloro-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1, 6)naphthyridine.
 19. The compound as defined in claim 1 formula (I) which is: 2-benzyl-8-chloro-10-(p-chlorophenyl)-1,2,3,4-tetrahydrobenzo(b)(1, 6)naphthyridine.
 20. The compound as defined in claim 1 formula (I) which is: 2-benzyl-8-chloro-1,2,3,4-tetrahydro-10-(p -methoxyphenyl)benzo(b)(1,6)naphthyridine.
 21. The compound as defined in claim 1 formula (I) which is; 1, 2,3,4-tetrahydro-1,1,3,3-tetramethyl-10-(p-tolyl)benzo(b)(1, 6)naphthyridine.
 22. The compound as defined in claim 1 formula (I) which is; 6-chloro-1,2,3,4-tetrahydro-1,1,3,3-tetramethyl-10 -phenylbenzo(b)(1,6)naphthyridine.
 23. The compound as defined in claim 1 formula (I) which is: 7, 8-dimethoxy-1,2,3,4-tetrahydro-1,1,3,3-tetramethyl-10-(p -methoxyphenyl)benzo(b)(1,6)naphthyridine.
 24. The compound as defined in claim 1 formula (I) which is: 7-chloro-1,2,3,4-tetrahydro-2-methyl-10-(2-thienyl)-benzo(b)(1, 6)naphthyridine.
 25. The compound as defined in claim 1 formula (I) which is: 7-chloro-1,2,3,4-tetrahydro-1,1,3,3-tetramethyl-10-(p -methylthiophenyl)benzo(b)(1,6)naphthyridine.
 26. The compound as defined in claim 1 formula (I) which is: 2-benzyl-7-chloro-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1, 6)naphthyridine.
 27. The compound as defined in claim 1 formula (I) which is: 8-chloro-1,2,3,4-tetrahydro-1,1,2,3,3-pentamethyl-10 -phenylbenzo(b)(1,6)naphthyridine.
 28. The compound as defined in claim 1 formula (I) which is: 1, 2,3,4-tetrahydro-2-phenethyl10-phenylbenzo(b)(1,6)naphthyridine.
 29. The compound as defined in claim 1 formula (I) which is: 2-benzyl-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1,6)naphthyridine.
 30. The compound as defined in claim 1 formula (I) which is: 3-(8-chloro-1,2,3,4-tetrahydro-10-phenylbenzo(b)(1,6)naphthyridin-2-yl)-5,5 -dimethyl-2-cyclohexen-1-one.
 31. The compound as defined in claim 1 formula (I) which is: 10-anilino-7-chloro-1,2,3,4-tetrahydro-2-methylbenzo(b)(1, 6)naphthyridine.
 32. The compound as defined in claim 1 formula (I) which is: 7-chloro-1,2,3,4-tetrahydro-2-methyl-10-phenoxybenzo(b)(1, 6)naphthridine.
 33. The compound as defined in claim 1 formula (I) which is: 10-(o-aminoanilino)-7-chloro-1,2,3,4-tetrahydro-2-methylbenzo(b)(1, 6)naphthyridine.
 34. The compound as defined in claim 1 formula (I) which is: 8-chloro-1,2,3,4-tetrahydro-2-methyl-10-phenoxybenzo(b)(1, 6)naphthyridine.
 35. The compound as defined in claim 1 formula (I) which is: 10-anilino-8-chloro-1,2,3,4-tetrahydro-2-methylbenzo(b)(1, 6)naphthyridine.
 36. The compound as defined in claim 1 formula (I) which is: 8-chloro-1,2,3,4-tetrahydro-2-methyl-10-((3 -dimethylaminopropyl)amino)benzo(b)(1,6)napthyridine.
 37. The compound as defined in claim 1 formula (I) which is: 7-chloro-1,2,3,4-tetrahydro-2-methyl-10-phenthiobenzo(b)(1, 6)naphthyridine.
 38. The compound as defined in claim 1 formula (I) which is: 10-(3-aminopropylthio)-8-chloro-1,2,3,4-tetrahydro-2 -methylbenzo(b)(1,6)naphthyridine.
 39. The compound as defined in claim 1 formula (I) which is: 1-(7-chloro-1,2,3,4-tetrahydro-2-methylbenzo(b)(1,6)naphthyridin-10-yl) -2phenylhydrazine.
 40. The compound as defined in claim 1 formula (I) which is: (8-chloro-1,2,3,4-tetrahydro-2-methylbenzo(b)(1,6)-naphthyridin-10 -yl)hydrazine.
 41. A process for the production of a compound having the formula: wherein R and R1, are the same and are selected from the group consisting of hydrogen, halogen, and lower alkoxy; R3 is selected from the group consisting of hydrogen, lower alkyl, phen(lower)alkyl, benzoyl, halo(lower)alkanoyl, dihalo(lower) alkanoyl, di(lower)alkylamino(lower) alkanoyl, di-(lower)alkylamino(lower)alkyl, dihydroxy(lower)alkyl and 5,5-dimethyl-3-oxo-1-cyclohexen-1-yl; R4 and R5 are both selected from the group consisting of hydrogen and dimethyl, wherein the lower alkyl group or the lower alkyl moiety in R, R1, or R3 is from one to six carbon atoms, which comprises contacting a 2-aminobenzoitrile having the formula: wherein R and R1 are defined as above, with a 4-piperidone having the formula: wherein R3, R4 and R5 are defined as above, in the presence of a strong acid selected from the group consisting of polyphosphoric, trifluoroacetic, acetic, benzensulfonic, toluenesulfonic, methyl sulfonic, and ethylsulfonic, at a temperature that is in the range from about 140* to about 200* C. for a period of from about one-half to about 2 hours.
 42. A process as described in claim 41 wherein the strong acid is polyphosphoric acid.
 43. A process as described in claim 41 wherein the strong acid is polyphosphoric acid and the reaction is conducted at about 150* C. for about 1 hour. 